24-1066 Badger Helicopters Inc. v. Federal Aviation Administration; U.S. Department of the Interior, National Parks Service

United States Court of Appeals
For the Eighth Circuit
___________________________
Nos. 24-1065/24-1066
___________________________
Badger Helicopters Inc.; Black Hills Aerial Adventures, Inc.; Rushmore
Helicopters, Inc.
Petitioners
v.
Federal Aviation Administration; U.S. Department of the Interior, National Parks
Service
Respondents
Coalition to Protect America’s National Parks; Public Employees for
Environmental Responsibility
Intervenors
------------------------------
Black Hills Helicopters, Inc.
Amicus on Behalf of Respondent
____________
Petitions for Review of an Order of the
Federal Aviation Administration
____________
Submitted: March 18, 2025
Filed: September 4, 2025
____________

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Before COLLOTON, Chief Judge, ERICKSON and GRASZ, Circuit Judges.
____________
GRASZ, Circuit Judge.
This case involves the federal government’s regulation of sightseeing air tours
over two units of the National Park System, specifically Mount Rushmore National
Memorial and Badlands National Park. In 2023, federal agencies issued air tour
management plans for those parks, banning all commercial air tours over them. Air
tour companies petitioned this court, arguing the agencies’ decisions must be vacated
because they were arbitrary and capricious. Concluding otherwise, we deny the
petitions to vacate the plans.
I. Background
In 2000, Congress passed the National Parks Air Tour Management Act (Air
Tour Management Act), which required commercial vendors seeking to conduct air
tours over units of the National Park System and certain tribal lands to first obtain
authorization from the Federal Aviation Administration (FAA). See Pub. L. No.
106-181, §§ 801-809, 114 Stat. 61, 185–94 (codified as amended at 49 U.S.C.
§ 40128). The Air Tour Management Act provides that the FAA, “in cooperation
with” the National Park Service, “shall establish an air tour management plan . . .
whenever a person applies for authority to conduct a commercial air tour operation
over” a national park or tribal land. 49 U.S.C. § 40128(b)(1)(A). These air tour
management plans (ATMPs) must go through notice and comment and include an
environmental decision in accordance with the National Environmental Policy Act
(NEPA). See id. § 40128(b)(2), (b)(4)(B). ATMPs may “prohibit” air tours entirely
or place certain conditions on them, such as “maximum or minimum altitudes,”
“time-of-day restrictions,” “maximum number of flights per unit of time,” and
“mitigation of noise, visual, or other impacts.” Id. § 40128(b)(3)(A)–(B).
Recognizing it could take time to implement ATMPs, Congress directed the FAA to

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“grant interim operating authority” to existing air tour operators.
Id. § 40128(c)(1), (c)(3).
The agencies began formulating ATMPs for Mount Rushmore National
Memorial and Badlands National Park (Parks). In 2004, the FAA published a notice
of intent to prepare environmental assessments for the Parks. Notice of
Environmental Assessment for Badlands National Park ATMP, 69 Fed. Reg. 20658
(Apr. 16, 2004); Notice of Environmental Assessment for Mount Rushmore National
Memorial ATMP, 69 Fed. Reg. 20660 (Apr. 16, 2004). But the work stalled. This
was not unique, as a decade after the enactment of the Air Tour Management Act,
the agencies had not implemented ATMPs for any parks. So in 2012, Congress
amended the Air Tour Management Act to permit the agencies to enter into voluntary
agreements in lieu of ATMPs. See FAA Modernization and Reform Act of 2012,
Pub. L. No. 112-95, § 501, 126 Stat. 11, 100–03 (codified at 49 U.S.C. § 40128).
The voluntary agreements required fewer administrative hurdles, and the agencies
thus focused on implementing these instead of ATMPs.
After further delays of agency action, organizations representing national park
employees, visitors, and hiking guides filed a petition for a writ of mandamus in the
D.C. Circuit. See In re Pub. Emps. for Env’t Resp. (In re PEER), 957 F.3d 267, 271
(D.C. Cir. 2020). These organizations asked the D.C. Circuit to compel the agencies
to establish ATMPs or voluntary agreements within two years at certain parks. Id.
In response to the litigation, the agencies developed a schedule for bringing seven
parks, including the two at issue here, into compliance with the Air Tour
Management Act. Id. The D.C. Circuit granted the writ for mandamus, ordering the
agencies to adopt ATMPs or voluntary agreements for every park. Id. at 275.
In 2020, while In re PEER was being considered by the D.C. Circuit, the
agencies notified those companies that held interim operating authority for the Parks
that the agencies were terminating their voluntary agreement negotiations and
transitioning to developing ATMPs. The agencies claimed they were changing
course because one of the active tour operators was unwilling to participate in the

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voluntary agreement process. The hold-out tour operator had less than 1% of the
interim operating authority allowance per year for each of the Parks. Later that year,
the FAA published an official notice of its decision to develop ATMPs for twenty-
three parks, including those at issue here. Notice of Intent to Complete ATMPs at
23 National Park Units, 85 Fed. Reg. 55060 (Sept. 3, 2020).
For the Parks, the agencies considered four ATMP alternatives: (1) allowing
the current interim operating authority air tours to continue without change;
(2) prohibiting air tours; (3) allowing a certain total number of air tours from May 1
through September 30 with daily limits, minimum altitudes, and prescribed routes;
and (4) allowing a lower total of air tours during a shorter time period with daily
limits, minimum altitudes, and prescribed routes. Ultimately, in 2023, the agencies
issued final ATMPs for the Parks (the Plans), prohibiting all commercial air tours
over the Parks and the area within a half mile of the Parks’ boundaries, except for
limited authorized purposes. The agencies’ final decisions explained that air tours
negatively affected visitor experience, wildlife, and tribal cultural experiences. The
agencies thus believed banning air tours best fit the goals of the Parks.
Tour operators — Badger Helicopters Inc., Black Hills Aerial Adventures
Inc., and Rushmore Helicopters Inc. (Petitioners) — timely filed petitions for review
(Petitions) with this court, arguing the Plans are arbitrary and capricious, an abuse
of discretion, and otherwise contrary to law. The agencies urge this court to deny
the Petitions and uphold the Plans. We permitted Public Employees for
Environmental Responsibility and the Coalition to Protect America’s National Parks
to intervene and also defend the Plans.
Petitioners moved to stay the Plans pending further review, but this court
denied their motion. The petitioners, agencies, and intervenors all moved to
supplement the administrative record, which we considered with the merits of the
Petitions and now deny the motions. See Rochling v. Dep’t of Veteran Affs., 725
F.3d 927, 936 (8th Cir. 2013).

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II. Analysis
This case comes to us pursuant to 49 U.S.C. § 46110(a), which allows “a
person disclosing a substantial interest in an order issued by” the FAA, in whole or
in part under statutory sections including the relevant section, to “apply for review
of the order by filing a petition for review in . . . the court of appeals of the United
States for the circuit in which the person resides or has its principal place of
business.” 49 U.S.C. § 46110. See also id. § 40128(b)(5) (“An [ATMP] developed
under this subsection shall be subject to judicial review.”). Because Petitioners’
principal places of business are in South Dakota, we have jurisdiction to review the
Petitions.
Petitioners ask us to review whether the Plans comply with the Air Tour
Management Act, NEPA, and the Administrative Procedure Act (APA). Under the
APA, we must “hold unlawful and set aside agency action, findings, and conclusions
found to be — (A) arbitrary, capricious, an abuse of discretion, or otherwise not in
accordance with law.” 5 U.S.C. § 706(2)(A). In conducting our analysis, we
“review the whole record or those parts of it cited by a party, and due account shall
be taken of the rule of prejudicial error.” Id. § 706.
An agency action is “arbitrary and capricious if the agency has relied on
factors which Congress has not intended it to consider, entirely failed to consider an
important aspect of the problem, offered an explanation for its decision that runs
counter to the evidence before the agency, or is so implausible that it could not be
ascribed to a difference in view or the product of agency expertise.” Motor Vehicle
Mfrs. Ass’n of U.S., Inc. v. State Farm Mut. Auto. Ins., 463 U.S. 29, 43 (1983). To
comply with this standard, “the agency must examine the relevant data and articulate
a satisfactory explanation for its action including a ‘rational connection between the
facts found and the choice made.’” Id. (quoting Burlington Truck Lines, Inc. v.
United States, 371 U.S. 156, 168 (1962)). In short, “a court asks not whether it
agrees with the agency decision, but rather only whether the agency action was

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reasonable and reasonably explained.” Seven Cnty. Infrastructure Coal. v. Eagle
County, 145 S. Ct. 1497, 1511 (2025).
A. Ending Voluntary Agreement Negotiations
Petitioners first claim the Plans are arbitrary and capricious because the
agencies ended the voluntary agreement process with Petitioners without a
satisfactory explanation. Petitioners recognize the Air Tour Management Act allows
the agencies to choose between pursuing voluntary agreements or ATMPs. Indeed,
the subsection on voluntary agreements states that “[a]s an alternative to an air tour
management plan,” the agencies “may enter into a voluntary agreement with a
commercial air tour operator.” 49 U.S.C. § 40128(b)(7). We find no reason to
vacate the Plans based on the agencies’ choice to develop ATMPs.
The agencies explained to Petitioners at the time that they were pivoting to
ATMPs that they were doing so because one of the tour operators refused to
participate in the voluntary agreement process. Though the uncooperative tour
operator held less than 1% of the interim operating authority, our role is not to
second-guess the wisdom of the agencies’ decision as long as it is reasonable. See
FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515 (2009) (explaining an
agency “need not demonstrate to a court’s satisfaction that the reasons for the new
policy are better than the reasons for the old one”). Under pressure from
organizations seeking a writ of mandamus in the D.C. Circuit, see In re PEER, 957
F.3d at 271, the agencies anticipated the obstacle of an uncooperative operator and
chose a different path. As explained in their official notice of termination and intent
to pursue ATMPs, the agencies recognized their past efforts to comply with the Air
Tour Management Act and the D.C. Circuit requiring them to bring twenty-three
parks into compliance with the Air Tour Management Act. See Notice of Intent to
Complete ATMPs at 23 National Park Units, 85 Fed. Reg. at 55060–61. Rather than
having a voluntary agreement that did not cover all tour operators and having to deal
with one entity who would not participate, the agencies developed ATMPs. The
agencies’ switch to ATMPs pursuant to the governing statute was not arbitrary or

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capricious. See Marin Audubon Soc’y v. FAA, 121 F.4th 902, 917–18 (D.C. Cir.
2024) (concluding “it was not arbitrary for the Agencies to reverse course” when
“the Agencies acknowledged their change of course and provided a reasonable
explanation for it”).
B. Alleged Violations of NEPA
Petitioners next raise three arguments about how the Plans issued under the
Air Tour Management Act are arbitrary and capricious because they violated certain
NEPA-related provisions. The Air Tour Management Act requires ATMPs to
include an “environmental decision document” under NEPA. See 49 U.S.C.
§ 40128(b)(2). Based on this requirement, Petitioners argue the agencies violated
NEPA by failing to use reliable data, failing to consider a reasonable range of
alternatives, and failing to consider aviation safety. Before turning to those
arguments, we first address the agencies’ argument that Petitioners may not
challenge the Plans on NEPA grounds because Petitioners’ interests are not within
NEPA’s zone of interests.
i. Zone of Interests
The Supreme Court “has long held that a person suing under the APA must
satisfy not only Article III’s standing requirements, but an additional test: The
interest he asserts must be ‘arguably within the zone of interests to be protected or
regulated by the statute’ that he says was violated.” Match-E-Be-Nash-She-Wish
Band of Pottawatomi Indians v. Patchak, 567 U.S. 209, 224 (2012) (quoting Ass’n
of Data Processing Serv. Orgs., Inc. v. Camp, 397 U.S. 150, 153 (1970)). The zone-
of-interests test “is not meant to be especially demanding.” Id. at 225 (quoting
Clarke v. Sec. Indus. Ass’n, 479 U.S. 388, 399 (1987)). The word “arguably” means
that “the benefit of any doubt goes to the plaintiff.” Id. A suit will thus fail the zone-
of-interests test “only when a plaintiff’s ‘interests are so marginally related to or
inconsistent with the purposes implicit in the statute that it cannot reasonably be

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assumed that Congress intended to permit the suit.’” Id. (quoting Clarke, 479 U.S.
at 399).
“Because the APA provides an omnibus cause of action for violations of other
statutes, the ‘relevant statute’ for an APA zone-of-interests analysis is not the APA
itself, but the statute under which the relevant agency acted.” FDA v. R.J. Reynolds
Vapor Co., 145 S. Ct. 1984, 1991 n.4 (2025). “Whether a plaintiff comes within the
zone of interests is an issue that requires us to determine, using traditional tools of
statutory interpretation, whether a legislatively conferred cause of action
encompasses a particular plaintiff’s claim.” Lexmark Int’l, Inc. v. Static Control
Components, Inc., 572 U.S. 118, 127 (2014) (quotations omitted).
The agencies argue that Petitioners assert solely the economic interests of their
for-profit air tour businesses, so they are outside the zone of interests protected by
NEPA. Petitioners respond by arguing that their challenges to the Plans are based
on the Air Tour Management Act, which expressly requires NEPA compliance, and
that they are therefore within the zone of interests to bring NEPA claims under the
Air Tour Management Act. We agree with Petitioners.
Here, the agencies “acted” under the Air Tour Management Act to develop
the Plans. See R.J. Reynolds Vapor Co., 145 S. Ct. at 1991 n.4. The objective of
these ATMPs is “to develop acceptable and effective measures to mitigate or prevent
the significant adverse impacts, if any, of commercial air tour operations upon the
natural and cultural resources, visitor experiences, and tribal lands.” 49 U.S.C.
§ 40128(b)(1)(B) (emphasis added). The Air Tour Management Act directly
regulates Petitioners’ commercial air tour operations. See id. § 40128(a)(1) (“A
commercial air tour operator may not conduct commercial air tour operations over a
national park . . . except . . . in accordance with any applicable air tour management
plan . . . .”). The Air Tour Management Act also expressly provides that an ATMP
“shall be subject to judicial review,” id. § 40128(b)(5), and another statutory section
provides that for some FAA orders, like those at issue here, “a person disclosing a
substantial interest in” those orders “may apply for review of the order by filing a

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petition for review in” a federal court of appeals, id. § 46110(a). In fact, the Plans
specifically discussed the right to appeal the Plans provided by 49 U.S.C. § 46110.
Congress clearly intended to allow Petitioners to challenge the Plans.
The Air Tour Management Act also expressly provides that, “[i]n establishing
an air tour management plan,” the agencies “shall each sign the environmental
decision document required by section 102” of NEPA. 49 U.S.C. § 40128(b)(2). It
acknowledges that an environmental decision document “may include a finding of
no significant impact, an environmental assessment, or an environmental impact
statement and the record of decision for the air tour management plan.” Id. Because
the NEPA environmental analysis is statutorily part of the ATMP process, the
Petitioners’ legislatively conferred ability to challenge the Plans encompasses their
NEPA-related claims. See Lexmark, 572 U.S. at 127; Patchak, 567 U.S. at 225–28.
We conclude Petitioners may challenge aspects of the underlying environmental
document produced pursuant to NEPA and required under the Air Tour Management
Act.1
1 The agencies primarily rely on two Eighth Circuit decisions to argue
Petitioners cannot use NEPA to challenge the Plans. See Cent. S.D. Coop. Grazing
Dist. v. Sec’y of the U.S. Dep’t of Agric., 266 F.3d 889, 896–97 (8th Cir. 2001);
Rosebud Sioux Tribe v. McDivitt, 286 F.3d 1031, 1038–39 (8th Cir. 2002). But since
those decisions, “the Supreme Court has greatly narrowed the doctrine of prudential
standing,” so we exercise caution before expanding those cases to address
circumstances involving the Air Tour Management Act. See Carson v. Simon, 978
F.3d 1051, 1058 (8th Cir. 2020) (citing Lexmark, 572 U.S. at 127). Besides,
“[i]ndividuals motivated in part by protection of their own pecuniary interest can
challenge administrative action under NEPA provided that their environmental
concerns are not so insignificant that they ought to be disregarded altogether.”
Robinson v. Knebel, 550 F.2d 422, 425 (8th Cir. 1977) (concluding landowners were
within NEPA’s zone of interests when their tillable land, ability to hunt, and farming
operations were at stake). Here, Petitioners have environmental concerns related to
the Plans because Petitioners’ business of sightseeing relies on the environmental
quality and sustainability of the Parks. Cf. Friends of the Boundary Waters
Wilderness v. Dombeck, 164 F.3d 1115, 1126 (8th Cir. 1999) (concluding plaintiffs’
claims were within the zone of interests when they asserted “their own inability to

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ii. NEPA Arguments
Turning to the NEPA-related arguments, we are guided by the Supreme
Court’s recent reminder that “NEPA is a procedural cross-check, not a substantive
roadblock.” See Seven Cnty., 145 S. Ct. at 1507. “Under NEPA, an agency’s only
obligation is to prepare an adequate report.” Id. at 1511. The statute’s procedural
requirement is intended “to insure a fully informed and well-considered decision,
not necessarily a decision the judges of the Court of Appeals or [the Supreme Court]
would have reached had they been members of the decisionmaking unit of the
agency.” Id. at 1514 (quoting Vermont Yankee Nuclear Power Corp. v. Nat. Res.
Def. Council, Inc., 435 U.S. 519, 558 (1978)). In short, “the central principle of
judicial review in NEPA cases is deference.” Id. at 1511.2
With this in mind, we turn to the environmental assessments prepared for
these Plans. The assessments analyzed the four alternatives considered by the
agencies and the impacts of those alternatives on several environmental impact
categories: noise and noise-compatible land use; air quality and climate change;
biological resources; cultural resources; wilderness; visitor use and experience and
other recreational opportunities; environmental justice and socioeconomics; visual
fully enjoy the BWCA Wilderness as a result of the [agency’s] visitor use
restrictions, a claim which is closely related to the physical environment”).
2Seven County’s emphasis on deference has even greater force here because
we deal with only an environmental assessment, whereas there the agency had to
prepare an environmental impact statement (EIS). See 145 S. Ct. at 1510. An EIS
addresses agency action reasonably foreseen to have “significant effect” on the
environment and requires “a detailed written statement.” 42 U.S.C. §§ 4336(b)(1),
4336e(6). In contrast, an environmental assessment is “a concise public document”
designed to determine what environmental impact an agency action may have and
whether an EIS is necessary. See id. § 4336(b)(2); Newton Cnty. Wildlife Ass’n v.
Rogers, 141 F.3d 803, 809 (8th Cir. 1998). Since an environmental assessment
demands a less onerous analysis, we will not impose stricter judicial review on it
than we would for an EIS.

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effects; and Department of Transportation Act Section 4(f) resources.3 Petitioners’
challenge focuses primarily on three aspects of the environmental assessments:
(a) data and resources relied upon; (b) number of alternatives considered; and
(c) aviation safety. We address each in turn.
a. Data and Resources
Petitioners first argue that the agencies failed to “make use of reliable data
and resources” as required by NEPA. See 42 U.S.C. § 4332(E). Petitioners criticize
the agencies’ choice of data in conducting their noise analyses and determinations
about potentially affected animal species in the Parks. We find no error requiring us
to vacate the Plans.
Starting with the agencies’ noise analyses, Petitioners do not challenge the
agencies’ modeling, but rather the underlying inputs used for the modeling,
specifically the flight operation data and the non-air tour noise. They argue the
agencies inadequately analyzed the impact of air tours on noise in the Parks because
they used flight operation data collected from tour operators in 2019 and certain
noise data collected in 2003.
For their noise impact analyses, the agencies used the FAA Aviation
Environmental Design Tool computer program to model aircraft noise exposure for
the existing operations. The program requires certain data inputs to model the
predicted impacts of different plan alternatives. For inputs related to aircraft data,
the agencies used the aircraft type, operational information, and flight route
information that they obtained from the operators in 2019. They also took the three-
year average of air tours from 2017 to 2019. For data on the Park Service’s
administrative flights for the Badlands National Park, they used average hours for
the Park Service’s administrative flights from 2011 to 2022. And for inputs related
3 Section 4(f) resources include “the natural beauty of the countryside and
public park and recreation lands, wildlife and waterfowl refuges, and historic sites.”
See 49 U.S.C. § 303(a), (f)(1).

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to natural ambient and existing ambient noise, the agencies used data from published
reports detailing 2003 sound level measurements taken at multiple locations within
the Parks.
The agencies used a three-year average from 2017 to 2019 “because they
reflected relatively current air tour conditions, represented reliable operator
reporting of air tours, accounted for variations across multiple years, were available
during the planning effort, and excluded years that were atypical due to the COVID-
19 pandemic.” The agencies “decided against using 2021 or 2022 data due to
continued abnormalities associated with the COVID-19 pandemic and the
unavailability of reporting data for 2021 or 2022 during most of the planning effort.”
Petitioners claim the flight routes and altitudes in 2019 were outdated because they
modified their tours in 2021. Petitioners fault the agencies for not requesting updates
on their flight operation information and instead using the data the tour operators
had already provided in 2019. But this data choice does not make the Plans arbitrary
or capricious.
Adopting Petitioners’ position would mean, as the agencies developed the
Plans, tour operators could change their flight patterns at any time and require the
agencies to redo their analyses. At the time the agencies were developing the Plans,
the interim operating authority did not provide any operating conditions for air tours
other than an annual limit of flights. The agencies recognized this reality in their
draft environmental assessments, noting that under the no-action alternative,
“[r]outes and altitudes may change, depending on an operator’s preference to change
routes or fly higher or lower than they currently are flying.” Thus, requiring up-to-
date information about the operators’ current flight operations here “would render
agency decisionmaking intractable, always awaiting updated information only to
find the new information outdated by the time a decision is made.” See Marsh v.
Or. Nat. Res. Council, 490 U.S. 360, 373 (1989). The agencies’ choice of flight data
was reasonable because it relied on reliable data, which was in the agencies’ view,
“the most accurate and current data available during the period that th[ese Plans

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were] being drafted.” See U.S. Air Tour Ass’n v. FAA, 298 F.3d 997, 1011 (D.C.
Cir. 2002) (quotation omitted).
Petitioners also argue that the agencies acted arbitrarily by relying on natural
and ambient noise data from 2003, rather than investigating current conditions, when
comparing “the noise impact of the existing operations to the Parks’ natural ambient
conditions and to the overall acoustic environment of the Parks.” Though the
agencies’ use of twenty-year-old data for some inputs is somewhat concerning,
Petitioners do not argue the agencies had been given more recent data. Cf. Dow
AgroSciences LLC v. Nat’l Marine Fisheries Serv., 707 F.3d 462, 473 (4th Cir. 2013)
(holding agency acted arbitrarily and capriciously when the agency “recognized that
it was relying on outdated data and that it had been presented with more recent data,
but it chose to continue relying on the outdated data without explaining why”). Nor
do they contest the accuracy of the past reports, arguing only that the data is older
than they would prefer. They thus ask us to speculate the current natural and ambient
noise environment changed so much from 2003 to 2023 that the agencies were
required to undertake a new study. Yet they do not explain how the natural noise
would have changed in the last twenty years to impact the data. And as to ambient
noise, they cite vague extra-record evidence about road construction, maintenance
projects, and changed travel patterns. We are unpersuaded that relying on the 2003
data for parts of the agencies’ noise analyses renders the Plans arbitrary or
capricious, particularly in light of NEPA’s instruction that an agency “is not required
to undertake new scientific or technical research unless” that “research is essential
to a reasoned choice among alternatives, and the overall costs and time frame of
obtaining it are not unreasonable.” See 42 U.S.C. § 4336(b)(3). The same goes for
the flight operation data and the administrative flight data. Whatever weakness the
data may have had from a lapse of time or varying time periods did not nullify its
ability to show the potential noise impact of the various plan alternatives and to
inform the agencies’ decision-making.
From a broader perspective, the data selections were only part of the noise
analyses, which were only part of the agencies’ larger environmental analyses,

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which were only part of the agencies’ considerations for their final decisions. See
Friends of the Boundary Waters Wilderness v. Dombeck, 164 F.3d 1115, 1129 (8th
Cir. 1999) (“Even assuming the data was flawed in some respects, this one study
was not the only source of information used by the Forest Service in compiling the
Final EIS.”). And the “ultimate question” we must resolve is whether the agencies’
final decisions were “reasonable and reasonably explained,” not the adequacy of any
given component of the environmental assessments. Seven Cnty., 145 S. Ct. at 1514.
Though the agencies could have defined in greater detail the effect of the air tours
by undertaking newer studies, we must afford “substantial deference” to the
agencies’ choices in their NEPA analyses and “not micromanage” choices “about
the depth and breadth of [their] inquiry.” Id. at 1513. As “we have said, ‘when the
resolution of the dispute involves primarily issues of fact and analysis of the relevant
information requires a high level of technical expertise,” in this case noise
measurements in national parks and the potential noise change over a twenty-year
period, “we must defer to the informed discretion of the responsible federal
agencies.’” See Missouri ex rel. Bailey v. U.S. Dep’t of Interior, 73 F.4th 570, 581
(8th Cir. 2023) (quoting Cent. S.D. Coop. Grazing Dist. v. Sec’y of the U.S. Dep’t of
Agric., 266 F.3d 889, 894–95 (8th Cir. 2001)).
Moreover, “[e]ven if the agency’s data is flawed, if the agency has relied on a
number of findings and only some are erroneous, we must reverse and remand only
if ‘there is a significant chance that but for the errors the agency might have reached
a different result.’” Cent. S.D., 266 F.3d at 899 (quoting Friends of the Boundary
Waters Wilderness, 164 F.3d at 1129). Here, the agencies were concerned with
multiple considerations, such as the impact of air tours on visitors’ experiences and
statements by tribal nations in opposition to all air tours over the Parks, all of which
the Air Tour Management Act allowed the agencies to factor into their Plans. See
49 U.S.C. § 40128(b)(1)(B) (stating ATMPs should address adverse impacts on
visitor experience and tribal lands caused by air tours). Even if new noise
measurements would show an increase in certain types of noise from 2003 to 2023,
it would not make unreasonable the conclusion that air tours contribute additional
non-natural noise or other disturbances that detract from the congressionally

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authorized objectives stated in the Air Tour Management Act. Ultimately, there is
not a significant chance that changing certain noise inputs in the agencies’ noise
impact analyses would have led to different Plans, so there is no prejudicial error.
See 5 U.S.C. § 706.
Petitioners also challenge the agencies’ determinations about air tours
impacting bighorn sheep and peregrine falcons in the Parks. They claim that the
Plans noted “only speculative and generalized harm of noises to the species,” failing
to show air tours caused harms to the bighorn sheep and peregrine falcons. But “an
agency may weigh environmental consequences as the agency reasonably sees fit
under its governing statute and any relevant substantive environmental laws.” Seven
Cnty., 145 S. Ct. at 1507. Here, the agencies noted that air tours pass over a prime
area for bighorn sheep lambing in the Badlands Park and that 70% of the sheep in
the Park were lost in 2021 due to disease. As to the peregrine falcons, the agencies
noted that a pair nested in Mount Rushmore Park in 2020 had four offspring, none
of which survived. The agencies noted both species are susceptible to noise
disturbance and that stressors such as air tour noise could impact their populations.
The fact the agencies did not determine whether air tours directly caused the species’
population losses in the Parks, or that different flight altitudes and patterns may
cause less harm, does not make the agencies’ Plans arbitrary or capricious.
NEPA “is not about preventing ‘unwise’ agency action—just ‘uninformed’
action.” Missouri ex rel. Bailey, 73 F.4th at 579 (quoting Robertson v. Methow
Valley Citizens Council, 490 U.S. 332, 351 (1989)). We conclude the agencies’
determinations about the bighorn sheep and peregrine falcons do not merit us
vacating the Plans.
b. Alternatives
Petitioners’ second NEPA-related argument is that the agencies failed to
consider a reasonable range of alternatives. NEPA requires agencies to “study,
develop, and describe appropriate alternatives to recommended courses of action in

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any proposal which involves unresolved conflicts concerning alternative uses of
available resources.” 42 U.S.C. § 4332(H). But “[w]hen an agency has concluded
through an Environmental Assessment that a proposed project will have a minimal
environmental effect, the range of alternatives it must consider to satisfy NEPA is
diminished.” Cent. S.D., 266 F.3d at 897. An agency need not “pursue policy
alternatives that are contrary to the pertinent statutory goals, or do not fulfill a
project’s purpose.” Id. (citation omitted). “[A]n agency may revoke a standard if it
reasonably explains the available evidence and offers a rational connection between
that evidence and its choice.” Id. at 898. “[P]etitioners must establish that their
preferred route is within the range of alternatives that reasonably needed to be
considered.” Mo. Mining, Inc. v. Interstate Com. Comm’n, 33 F.3d 980, 984 (8th
Cir. 1994).
The agencies considered four plan alternatives for each Park during and after
the public commenting process: (1) allow current flight operations to continue
without change; (2) prohibit air tours; (3) restrict air tours through altitude
minimums and by limiting flight months, daily flights, and annual flights; and
(4) restrict air tours through altitude minimums and by further limiting flight months,
daily flights, and annual flights. Petitioners complain the agencies did not consider
alternatives that adjusted flight altitudes or routes.
While the agencies did not include alternatives that would have adjusted the
flight routes or altitudes from the current flight operations, they considered doing so
and concluded otherwise. For the Badlands Plan, the agencies considered adjusting
the altitudes but determined it was not feasible given the location of the current
private heliport near the Park boundary. Likewise, they considered moving the
routes but also determined that doing so and mitigating noise was not feasible
because it would result in flying over the Badlands’ Wilderness area, negatively
affecting Wilderness character. For Mount Rushmore, the agencies explained that
the park “is very small (only 1,278 acres), thus the agencies were not able to include
routes or altitude adjustments in Alternatives 3 or 4 due to safety concerns.”

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It is for Petitioners to establish their preferred alternative is within the range
of alternatives that reasonably needed to be considered. See Mo. Mining, Inc., 33
F.3d at 984. Yet they do not provide specific information about flight altitudes or
routes that could alleviate the agencies’ concerns, and the administrative record
shows the agencies considered and rejected including other alternatives like those
preferred by Petitioners. Again, “when the resolution of the dispute involves
primarily issues of fact and analysis of the relevant information requires a high level
of technical expertise, we must defer to the informed discretion of the responsible
federal agencies.” Missouri ex rel. Bailey, 73 F.4th at 581 (quotation omitted). For
these reasons, the agencies fulfilled the NEPA requirement to “study, develop, and
describe appropriate alternatives to recommended courses of action.” 42 U.S.C.
§ 4332(H); see also Friends of the Boundary Waters Wilderness, 164 F.3d at 1128
(explaining the court is guided by the rule of reason and considers whether the
agency “adequately sets forth sufficient information to allow the decision-maker to
consider alternatives and make a reasoned decision after balancing the risks of harm
to the environment against the benefits of the proposed action”). We find no
reversible error with the agencies’ consideration of alternatives to their
recommended course of action.
c. Aviation Safety
Petitioners’ third and final NEPA-related argument is that the Plans are
arbitrary and capricious because Petitioners allege the agencies failed to consider
aviation safety. In making their argument, they rely on 40 C.F.R. § 1501.3(b)(2)(iii)
(2020), which required agencies to consider adverse effects on “public health and
safety.” Id. Here, the Plans’ findings of no significant impact stated that “[t]he FAA
reviewed the ATMP to identify and address any safety concerns. The FAA also
reviewed all public comments received on the draft ATMP that raised safety
concerns.” The findings also stated that “[u]nder FAA regulations, the pilot-in-
command is always required to take action to ensure the safe operation of the
aircraft.” For Mount Rushmore, the FAA explained that it would “evaluate the
establishment of an operational plan in the area to enhance safety.” In response to

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comments on the proposed Mount Rushmore ATMP about aviation safety, the
agencies explained the FAA would “perform outreach with air tour operators and
other stakeholders to encourage the development of an operational plan to enhance
safety.” Moreover, both Plans explicitly provide that they may be amended if the
FAA “determines that the ATMP is adversely affecting aviation safety and/or the
national aviation system.” Notably, these Plans will be implemented against the
backdrop of the FAA’s “rules governing the operation of aircraft within the United
States.” See 14 C.F.R. § 91.1. We therefore conclude Petitioners’ consideration of
impact on aviation safety outside the Parks’ boundaries does not render the Plans
arbitrary or capricious.
III. Conclusion
For the foregoing reasons, we conclude the agencies’ decisions were
reasonable and therefore deny the petitions to vacate the air tour management plans.
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