FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

CASEY CLARKSON, 

Plaintiff-Appellant,

 v. 

ALASKA AIRLINES, INC.; 

HORIZON AIR INDUSTRIES, INC., 

Defendants-Appellees.

No. 21-35473 

D.C. No. 2:19-cv00005-TOR 

OPINION

Appeal from the United States District Court

for the Eastern District of Washington

Thomas O. Rice, District Judge, Presiding

Argued and Submitted October 21, 2022

Portland, Oregon

Filed February 1, 2023

Before: Richard A. Paez and Bridget S. Bade, Circuit 

Judges, and Haywood S. Gilliam, Jr.,* District Judge.

Opinion by Judge Paez

* The Honorable Haywood S. Gilliam, Jr., United States District Judge 

for the Northern District of California, sitting by designation.
2 CLARKSON V. ALASKA AIRLINES, INC. 

SUMMARY**

Labor Law 

The panel reversed the district court’s grant of summary 

judgment in favor of defendants Alaska Airlines, Inc., and 

Horizon Air Industries, Inc., and remanded, in a class action 

brought under the Uniformed Services Employment and 

Reemployment Rights Act (USERRA) by Casey Clarkson, 

a commercial airline pilot and military reservist.

Clarkson alleged that because the airlines provided paid 

leave for non-military leaves, including jury duty, 

bereavement, and sick leave, the airlines were also required 

to pay pilots during short-term military leaves of thirty days 

or less.

Under USERRA § 4316(b)(1), “a person who is absent 

from a position of employment by reason of service in the 

uniformed services” shall be “deemed to be on furlough or 

leave of absence” and shall be “entitled to such other rights 

and benefits not determined by seniority as are generally 

provided by the employer” to other employees on nonmilitary furloughs or leaves of absence. Under 20 C.F.R. § 

1002.150, the “non-seniority rights and benefits to which an 

employee is entitled during a period of service are those that 

the employer provides to similarly situated employees.” If 

the benefits vary according to the type of leave, the 

employee must be given “the most favorable treatment 

accorded to any comparable form of leave when he or she 

** This summary constitutes no part of the opinion of the court. It has 

been prepared by court staff for the convenience of the reader.
CLARKSON V. ALASKA AIRLINES, INC. 3

performs service in the uniformed services.” To determine 

whether types of leave are comparable, the duration of the 

leave must be considered, as well as the purpose of the leave 

and the ability of the employee to choose when to take the 

leave. 

The panel held that the district court erred in concluding 

that no reasonable jury could find military leave comparable 

to non-military leave. In reaching this conclusion, the 

district court erred by comparing all military leaves, rather 

than just the short-term military leaves at issue here, with the 

comparator non-military leaves. The district court also erred 

by disregarding factual disputes about each of the three 

factors in the comparability analysis: duration, purpose, and 

control. The panel held that because factual disputes 

existed, comparability was an issue for the jury.

The panel therefore reversed and remanded. It instructed 

that on remand, the district court should consider in the first 

instance the issue whether “pay during leave” was a 

standalone benefit that the airlines provided under their 

collective bargaining agreements to any employee on leave.
4 CLARKSON V. ALASKA AIRLINES, INC.

COUNSEL

Jonathan E. Taylor (argued), Deepak Gupta, Peter RomerFriedman, and Robert Friedman, Gupta Wessler PLLC, 

Washington, D.C.; Adam T. Klein and Michael J. Scimone, 

Outten & Golden LLP, New York, New York; Vincent 

Chang, Block & Leviton LLP, San Francisco, California; R. 

Joseph Barton and Colin M. Downes, Block & Leviton LLP, 

Washington, D.C.; Matthew Z. Crotty, Crotty & Son Law 

Firm PLLC, Spokane, Washington; Thomas G. Jarrard, The 

Law Office of Thomas G. Jarrard PLLC, Spokane, 

Washington; for Plaintiff-Appellant.

Anton Metlitsky (argued), Mark W. Robertson, and Charles 

Mahoney, O’Melveny & Myers LLP, New York, New York; 

Jason Zarrow, O’Melveny & Myers LLP, Los Angeles, 

California; Tristan Morales, O’Melveny & Myers LLP, 

Washington, D.C.; Steven W. Fogg, Corr Cronin LLP, 

Seattle, Washington; Kathryn S. Rosen, Davis Wright 

Tremaine LLP, Seattle, Washington; for DefendantsAppellees.

David T. Raimer and Douglas W. Hall, Jones Day, 

Washington, D.C., for Amicus Curiae Airlines for America.
CLARKSON V. ALASKA AIRLINES, INC. 5

OPINION

PAEZ, Circuit Judge:

For over sixty years, our nation has encouraged military 

service by continually easing the burden on servicemembers 

who must juggle military duties with civilian jobs. In the 

Selective Training and Service Act of 1940, Congress 

ensured for the first time—but not the last—that veterans

returning to civilian jobs would not face discrimination on 

account of their service. Over the succeeding decades, reemployment rights were extended to military reservists and 

National Guardsmen. These protections remain all the more 

important today, as our nation relies on an all-volunteer 

military force. Indeed, just as the draft came to an end, 

Congress expanded servicemembers’ protections in the 

Veterans’ Reemployment Rights Act of 1974. Congress 

continued its tradition of recognizing the sacrifice and 

dedication of servicemembers in 1994 by enacting the 

Uniformed Services Employment and Reemployment 

Rights Act (“USERRA”). Today, USERRA § 4316(b)(1) 

requires employers to provide employees who take military 

leave with the same non-seniority rights and benefits as their 

colleagues who take comparable non-military leaves. See 38 

U.S.C. § 4316(b)(1); 20 C.F.R. § 1002.150(a). 

Casey Clarkson (“Clarkson”), a commercial airline pilot 

and military reservist, claims that his employers failed to 

abide by this rule. Clarkson alleges that because Alaska 

Airlines and Horizon Air Industries (collectively, the 

“Airlines”) provide paid leave for non-military leaves 

including jury duty, bereavement, and sick leave, the 

Airlines are also required to pay pilots during short-term 

military leaves. The district court disagreed, granting
6 CLARKSON V. ALASKA AIRLINES, INC.

summary judgment to the Airlines and concluding as a 

matter of law that military leave is not comparable to any 

other form of leave offered by the Airlines. We reverse. 

I. STATUTORY BACKGROUND

A.

Enacted in 1994, USERRA1 contains “the most 

expansive protection to servicemembers yet enacted . . . 

[and] entitle[s] reservists and other military personnel to 

certain employment benefits while on leave.” Travers v. 

Fed. Express Corp., 8 F.4th 198, 201 (3d Cir. 2021) (cleaned 

up).2 USERRA serves three primary purposes: (1) “[T]o 

encourage noncareer service in the uniformed services by 

eliminating or minimizing the disadvantages to civilian 

careers and employment which can result from such 

service”; (2) “to minimize . . . disruption . . . by providing 

for the prompt reemployment of [persons performing 

military service] upon their completion of such service”; and 

(3) “to prohibit discrimination against persons because of 

their service in the uniformed services.” 38 U.S.C. § 4301. 

In short, USERRA recognizes that those who serve in the 

military should be supported, rather than penalized, for their 

service. USERRA enables servicemembers to strike a

balance between fulfilling their military duties and civilian 

obligations, including civilian jobs, without suffering 

discrimination. See Travers, 8 F.4th at 199. While 

USERRA is “the most recent in a series of laws protecting 

1 Pub. L. No. 103-353, 108 Stat. 3149 (codified at 38 U.S.C. § 4301).

2 For a fuller recounting of the history of USERRA and its predecessor 

statutes, see Travers v. Fed. Express Corp., 8 F.4th 198 (3d Cir. 2021),

and Rogers v. City of San Antonio, 392 F.3d 758 (5th Cir. 2004). 
CLARKSON V. ALASKA AIRLINES, INC. 7

veterans’ employment and reemployment rights,” Rogers v. 

City of San Antonio, 392 F.3d 758, 762 (5th Cir. 2004),

Congress intended USERRA to build on the rights 

established in its predecessor statutes, including the 

Selective Training and Service Act of 1940 (“STSA”), Pub. 

L. No. 783, 54 Stat. 885, 890, and the Veterans’ 

Reemployment Rights Act of 1974 (“VRRA”), Pub. L. No. 

93-508, 88 Stat. 1578, 1594 (codified at 38 U.S.C. § 2021). 

See also Travers, 8 F.4th at 199-201. The “large body of 

case law that had developed under those statutes remain[s] 

in full force and effect.” Rogers, 392 F.3d at 762 (quoting 

20 C.F.R. § 1002.2). An understanding of the history of 

these protective statutes and the corresponding case law is 

thus critical to our evaluation of this case. 

USERRA’s predecessor statutes guaranteed that 

servicemembers who took leave from a civilian job for 

military service could return to that job without losing 

“seniority, status, or pay.” STSA, Pub. L. No. 783, § 8(b), 

54 Stat. 885, 890; VRRA, Pub. L. No. 93-508, § 2021(a), 88 

Stat. 1578, 1595. These rights were extended to military 

reserve members and National Guardsmen throughout the 

1950s and 1960s. See, e.g., Pub. L. No. 305, § 261(f), 69 

Stat. 598, 602 (1955); Pub. L. No. 86-632, § 5, 74 Stat. 467, 

468 (1960); accord Monroe v. Standard Oil Co., 452 U.S. 

549, 555 (1981); Rogers, 392 F.3d at 764. Reservists, 

however, did not receive “protection against discharges, 

demotions, or other discriminatory conduct once reinstated”

until 1968. Monroe, 452 U.S. at 556-60. At that time, 

Congress enacted what became § 2021(b)(3) of the VRRA,

3

3 Before 1974, veterans’ re-employment rights provisions were codified 

at 50 U.S.C. § 459. These provisions were recodified without 
8 CLARKSON V. ALASKA AIRLINES, INC.

which provides: “Any person [employed by a private 

employer] shall not be denied retention in employment or 

any promotion or other incident or advantage of employment 

because of any obligation as a member of a reserve 

component of the Armed Forces of the United States.” Pub. 

L. No. 90-491, 82 Stat. 790 (1968).

Both the House and Senate Reports on the proposed 

legislation explained that § 2021(b)(3) would “assure[] that 

these reservists will be entitled to the same treatment 

afforded their coworkers without such military obligation.” 

H.R. Rep. No. 90-1303, at 3 (1968); accord S. Rep. No. 90-

1477, at 1-2 (1968). By protecting reservists from 

discrimination, the provision would encourage voluntary 

military service. See Monroe, 452 U.S. at 557-60. In 1981, 

the Supreme Court clarified in Monroe that § 2021(b)(3) 

entitled reservists to equal, but not preferential, treatment as 

compared to their non-military coworkers. Id. at 557-66. 

Five years after the Court decided Monroe, the Third 

Circuit considered the application of § 2021(b)(3) in 

Waltermyer v. Aluminum Co., 804 F.2d 821 (3d Cir. 1986). 

There, the Third Circuit concluded that a National 

Guardsman was entitled to holiday pay for a holiday that 

occurred while he was on military leave because employees 

on non-military leaves, including jury duty, bereavement 

leave, and sick leave, received holiday pay. Id. at 825. 

Although the collective bargaining agreement limited 

holiday pay to employees who worked during the holiday 

week or employees on certain enumerated leaves (which did 

not include military leave), the court concluded that the list 

substantive change in the VRRA. See Coffy v. Republic Steel Corp., 447 

U.S. 191, 194 n.2 (1980). 
CLARKSON V. ALASKA AIRLINES, INC. 9

of enumerated leaves focused on “involuntary” leaves. Id. 

Because the National Guardsman’s military leave was also 

involuntary, the court held that it would be equitable, and not 

preferential, to require the employer to provide holiday pay 

under § 2021(b)(3). Id. 

Congress later codified the Waltermyer decision in 

USERRA § 4316(b)(1), the provision at issue here. As the 

House Report on the bill explained: 

The Committee intends to affirm the decision 

in Waltermyer v. Aluminum Co. of America,

804 F.2d 821 (3d Cir. 1986) that, to the extent 

the employer policy or practice varies among 

various types of non-military leaves of 

absence, the most favorable treatment 

accorded any particular leave would also be 

accorded the military leave, regardless of 

whether the non-military leave is paid or 

unpaid. 

H.R. Rep. 103-65, pt. 1, at 33-34 (1993); accord S. Rep. 103-

158, at 58 (1993). 

B.

Section 4316(b)(1) expanded non-seniority employment 

benefits for servicemembers, including reservists and 

Guardsmen, who must take leave from civilian jobs to 

perform their military duties. Under § 4316(b)(1), “a person 

who is absent from a position of employment by reason of 

service in the uniformed services” shall be “deemed to be on 

furlough or leave of absence,” and shall be “entitled to such 

other rights and benefits not determined by seniority as are 

generally provided by the employer” to other employees on 
10 CLARKSON V. ALASKA AIRLINES, INC.

non-military furloughs or leaves of absence. 38 U.S.C. § 

4316(b)(1).4

The Department of Labor’s (“DOL”) implementing 

regulation for § 4316(b)(1) explains that the “non-seniority 

rights and benefits to which an employee is entitled during a 

period of service are those that the employer provides to 

similarly situated employees by an employment contract, 

agreement, policy, practice, or plan in effect at the 

employee’s workplace.” 20 C.F.R. § 1002.150(a). The 

regulation then explains that if the benefits vary according to 

the type of leave, the employee must be given “the most 

favorable treatment accorded to any comparable form of 

leave when he or she performs service in the uniformed 

services.” Id. at § 1002.150(b) (emphasis added). The 

regulation also explains how to determine if types of leave 

are comparable: 

To determine whether any two types of leave 

are comparable, the duration of the leave may 

be the most significant factor to compare. 

For instance, a two-day funeral leave will not 

be “comparable” to an extended leave for 

service in the uniformed service. In addition 

to comparing the duration of the absences, 

4 Under USERRA, the term “rights and benefits” is defined as “the terms, 

conditions, or privileges of employment, including any advantage, profit, 

privilege, gain, status, account, or interest (including wages or salary for 

work performed) that accrues by reason of an employment contract or 

agreement or an employer policy, plan, or practice and includes rights 

and benefits under a pension plan, a health plan, an employee stock 

ownership plan, insurance coverage and awards, bonuses, severance pay, 

supplemental unemployment benefits, vacations, and the opportunity to 

select work hours or location of employment.” 38 U.S.C. § 4303(2).
CLARKSON V. ALASKA AIRLINES, INC. 11

other factors such as the purpose of the leave 

and the ability of the employee to choose 

when to take the leave should also be 

considered. 

Id. at § 1002.150(b). Clarkson challenges the Airlines’ 

compliance with this regulation. 

II. DISTRICT COURT PROCEEDINGS

Clarkson filed this action against the Airlines in 2019, 

alleging that the Airlines violated § 4316(b)(1) of USERRA 

by failing to pay pilots who took short-term military leave 

while paying pilots who took comparable non-military 

leaves. He filed the action on behalf of himself and all others

similarly situated. The district court certified a “Paid Leave 

Class” in August 2020, defined as: “All current or former 

Alaska or Horizon pilots who have taken short-term military 

leave from October 10, 2004 through the date of the 

judgment.” Although the certification order did not define 

short-term military leave, the parties and court understood it 

to mean military leaves of thirty days or less. Clarkson and 

the members of the class were or are employed as pilots by 

Alaska or Horizon. While employed, Clarkson and the other 

class members took at least one military leave of thirty days 

or less. These facts are undisputed. 

What the parties cannot agree on, however, is whether 

short-term military leave is comparable to the non-military 

leaves offered by the Airlines, namely jury duty, 

bereavement leave, or sick leave.5

 In seeking summary 

5 Clarkson also argues that vacation leave may be comparable to shortterm military leave. The Airlines do not address vacation leave, asserting 

that such argument is precluded because Clarkson did not specifically 

identify vacation leave as a comparator in his complaint. Clarkson’s 
12 CLARKSON V. ALASKA AIRLINES, INC.

judgment, the Airlines argued that military leave is not 

comparable to non-military leave as a matter of law. In the 

alternative, the Airlines argued that even if the leaves were

comparable, “pay during leave” is not a benefit offered in 

their collective bargaining agreements (“CBAs”) to which 

the class members are entitled. Clarkson did not address this 

second argument, and instead argued that a reasonable jury 

could find that some or all of the non-military leaves offered 

by the Airlines are comparable to short-term military leave. 

As in the district court, the parties’ arguments focus on

the three comparability factors outlined in the regulation: (1) 

duration of leave, (2) purpose of leave, and (3) ability of the 

employee to choose when to take the leave (also referred to 

as “control”). 20 C.F.R. § 1002.150(b). In the district court, 

each side submitted an expert report comparing the duration 

of military leave to the duration of other types of leave. The 

Airlines’ expert conducted his analysis using all military 

leaves rather than just short-term military leaves of thirty 

days or less, analyzed the frequency of leaves, and focused 

on the length of leaves at the highest percentiles rather than 

the average lengths. As a result, his comparator numbers 

look quite different from the numbers produced by 

Clarkson’s expert, who focused on the average, mode, and 

median days taken of short-term military leave. The parties 

complaint repeatedly references “other” types of leave besides jury duty, 

bereavement, and sick leave, and Clarkson included vacation as a 

comparator leave in his opposition to summary judgment. However, the 

district court did not address vacation leave as a comparator. Because it 

is clear that a reasonable jury could find jury duty, bereavement, or sick 

leave comparable to short-term military leave, we need not address 

vacation leave to reverse the grant of summary judgment. On remand, 

the district court may address vacation leave as a comparator in the first 

instance. 
CLARKSON V. ALASKA AIRLINES, INC. 13

also presented conflicting evidence about the purpose of 

military leave and the ability of pilots to control when they 

take such leave. The Airlines contend that pilots take 

military leave to pursue a parallel career, while Clarkson 

maintains that military leave allows pilots to perform a civic 

duty and public service. The Airlines also contend that pilots 

have near total control over when to take military leave, 

while Clarkson argues that the military schedule is not so 

flexible. 

On each factor, the district court determined there were 

no genuine issues of material fact and concluded that 

military leave is not comparable to any other leave as a 

matter of law. The district court thus did not address the 

“pay during leave” issue and granted summary judgment to 

the Airlines. Clarkson timely appealed.6 We reverse. 

III. STANDARD OF REVIEW

We review de novo a district court’s summary judgment 

ruling to determine whether “there are any genuine disputes 

of material fact and whether the district court correctly 

applied the relevant substantive law.” Reynaga v. Roseburg 

Forest Products, 847 F.3d 678, 685 (9th Cir. 2017) (quoting 

Dominguez-Curry v. Nevada Trans. Dep’t, 424 F.3d 1027, 

1033 (9th Cir. 2005)). “An issue of fact is genuine ‘if the 

evidence is such that a reasonable jury could return a verdict 

for the nonmoving party.’” Id. at 685-86 (quoting Villiarimo

v. Aloha Island Air, Inc., 281 F.3d 1054, 1061 (9th Cir. 

2002)). A grant of summary judgment is “proper only where 

there is no genuine issue of any material fact or where 

viewing the evidence and the inferences which may be 

drawn therefrom in the light most favorable to the adverse 

6 We have jurisdiction under 28 U.S.C. § 1291. 
14 CLARKSON V. ALASKA AIRLINES, INC.

party, the movant is clearly entitled to prevail as a matter of 

law.” Sandvik v. Alaska Packers Ass’n, 609 F.2d 969, 974 

(9th Cir. 1979) (quoting Smith v. Gross, 604 F.2d 639, 641 

(9th Cir. 1979)). As we discuss below, the district court 

failed to heed these summary judgment principles in its 

comparability analysis. 

IV. DISCUSSION

In entering judgment for the Airlines, the district court 

concluded that no reasonable jury could find military leave 

comparable to non-military leave. In reaching this 

conclusion, the district court erred by comparing all military 

leaves, rather than just the short-term military leaves at issue

here, with the comparator non-military leaves. The court 

also erred by disregarding countless factual disputes about 

each of the three factors in the comparability analysis: 

duration, purpose, and control. The court seemingly 

considered only the evidence presented by the Airlines when 

it concluded no reasonable jury could find for Clarkson. 

Because factual disputes exist, comparability is an issue for 

the jury.

A. Under USERRA, Courts Must Consider the 

Length of Leave at Issue

In concluding that military leave is not comparable to 

other leaves as a matter of law, the district court first agreed 

with the Airlines that military leave must be considered as a 

“general category of leave,” Clarkson v. Alaska Airlines, 

Inc., 2021 WL 2080199, at *4 (E.D. Wash. May 24, 2021),

rather than in an “individualized analysis.” Id. at *5. The 

district court thus decided that all military leaves taken by 

pilots at the Airlines—whether two days or two years—must 

be grouped together when assessing the most significant 

comparability factor: duration. 20 C.F.R. § 1002.150(b). 
CLARKSON V. ALASKA AIRLINES, INC. 15

Although we have not yet addressed whether military 

leave should be considered based on its length or 

categorically when assessing USERRA violations, we hold 

that examining the length of leave at issue is the correct 

approach. Cf. Paige v. California, 291 F.3d 1141, 1147 (9th 

Cir. 2002) (determining the proper comparator groups is a 

question of law). The plaintiff, as master of the complaint, 

can limit the request for recovery of benefits to specific, 

shorter military leaves. To follow the district court’s 

approach and consider military leaves categorically would 

render USERRA’s protections meaningless. Military leaves 

vary greatly in length, and the longest leaves can last years. 

Were we to adopt a categorical approach to military leaves, 

no other type of leave would look similar, and

servicemembers would not be protected under § 4316(b)(1). 

Indeed, the statute’s implementing regulation suggests

that the military leave at issue should be compared with the 

alleged comparable leaves. Section 1002.150 states that

duration is the most significant factor to compare when 

determining if “any two types of leave are comparable.” In 

context, “any two types of leave” must refer to (1) military 

leave and (2) another employer-offered leave. As the 

regulation explains, “a two-day funeral leave will not be 

‘comparable’ to an extended leave for service.” 20 C.F.R. 

1002.150(b). But while an “extended” military leave is not 

comparable to a “two-day funeral leave,” it is entirely 

possible that a two-day military leave is comparable to a 

two-day funeral leave. 

Although our sister circuits have not addressed this 

question directly, their opinions support the conclusion that 

a plaintiff may define his claim by the particular length of 

the military leave at issue. As the Seventh Circuit explained: 

“It is up to the employee to demonstrate that any given 
16 CLARKSON V. ALASKA AIRLINES, INC.

stretch of military leave is comparable to a form of 

nonmilitary leave that is accorded a benefit.” White v. 

United Airlines, Inc., 987 F.3d 616, 624 (7th Cir. 2021) 

(emphasis added).7 

We thus conclude that the district court erred when it 

compared non-military leaves offered by the Airlines to all 

military leaves taken by pilots at the Airlines. Clarkson 

limited his claim to military leaves of thirty days or less. 

Thus, the relevant question is whether such short-term leaves 

are comparable to the other leaves offered by the Airlines. 

As discussed next, this is a question for the jury. 

B. Whether Short-Term Military Leave Is 

Comparable to Other Types of Leaves Is a Jury 

Question

“Comparability is a question of fact.” Syufy Enters. v. 

Am. Multicinema, Inc., 793 F.2d 990, 1003 (9th Cir. 1986). 

It is thus a question for the jury unless “the facts of a case 

suggest that no reasonable jury could see enough 

commonality for a meaningful comparison.” Howell v. 

7 The district court acknowledged White but stated it “is not inclined to 

apply the Seventh Circuit’s White holding to this case, as the Ninth 

Circuit has not yet spoken on the issue.” Clarkson, 2021 WL 2080199 

at *5. The Fifth Circuit has also denied summary judgment in a similar 

§ 4316(b)(1) case, noting that there “are genuinely disputable issues as 

to the material facts of whether involuntary non-military leaves, not 

generally for extended durations . . . are comparable to each plaintiff’s

military leaves taken for service in the uniformed services.” Rogers, 392 

F.3d at 771-72 (emphasis added); see also Tully v. Dep’t of Just., 481 

F.3d 1367, 1368 (Fed. Cir. 2007) (holding that employee was not entitled 

to holiday pay because a two-and-a-half-year military leave was not 

comparable to other leaves); Waltermyer, 804 F.2d at 825 (holding that 

employee was entitled to holiday pay because a two-week military leave 

was comparable to other leaves).
CLARKSON V. ALASKA AIRLINES, INC. 17

Wexford Health Sources, Inc., 987 F.3d 647, 657 (7th Cir. 

2021) (quoting Rozumalski v. W.F. Baird & Assocs., Ltd., 

937 F.3d 919, 927 (7th Cir. 2019)) (holding that 

comparability in employment discrimination cases is a jury 

question); see also Wheeler v. Georgetown Univ. Hosp., 812 

F.3d 1109, 1116 (D.C. Cir. 2016) (same); Graham v. Long 

Island R.R., 230 F.3d 34, 39 (2d Cir. 2000) (same). 

The district court considered the three factors outlined in 

the regulation—duration, purpose, and control—and found 

that no jury could find in Clarkson’s favor given “significant 

differences” between military leave and non-military leave 

as to each factor. The district court thus granted the Airlines 

summary judgment because it found that there “are no 

genuine issues of material fact as to whether military leave 

is comparable to other forms of leave covered by the CBAs; 

they are not comparable.” Clarkson, 2021 WL 2080199 at 

*9. 

This conclusion was erroneous. At the summary 

judgment stage, “the judge’s function is not . . . to weigh the 

evidence and determine the truth of the matter[,] but to 

determine whether there is a genuine issue for trial.” 

Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 249 (1986). 

As explained below, the record evidence presents genuine 

issues of material fact as to each factor that, when viewed in 

the light most favorable to Clarkson, would allow a 

reasonable jury to find in his favor. 

1. Duration 

Duration is the “most significant factor” in the 

comparability analysis. 20 C.F.R. § 1002.150(b). After 

considering the evidence, the district court determined that 

“[g]iven the significant differences in duration and 

frequency, military leave is not comparable to jury duty, 
18 CLARKSON V. ALASKA AIRLINES, INC.

bereavement leave, and sick leave.” Clarkson, 2021 WL 

2080199 at *6. This holding ignored significant factual 

disputes over the leave data presented by the Airlines. The 

district court’s analysis was also flawed by including 

frequency as an integral factor in the duration analysis. 

a. Disputed statistical evidence 

Although the parties agree on the underlying dataset 

regarding the duration of military and non-military leaves, 

their agreement ends there. Each side’s expert used that 

dataset to present different opinions on the comparability of 

the duration of military and non-military leave. When 

parties “offer conflicting inferences drawn from the 

[statistical] evidence . . . there is a genuine dispute of 

material fact . . . and [the] action must proceed to trial.” 

Paige, 291 F.3d at 1147. It is for the jury, not the court, to

decide how to weigh these conflicting inferences. Tyson 

Foods, Inc. v. Bouaphakeo, 577 U.S. 442, 459 (2016) (“Once 

a district court finds evidence to be admissible, its 

persuasiveness is, in general, a matter for the jury.”); City of 

Pomona v. SQM N. Am. Corp., 750 F.3d 1036, 1049 (9th Cir. 

2014) (“Where two credible experts disagree, it is the job of 

the fact finder, not the trial court, to determine which source 

is more credible and reliable.”).

Instead of recognizing this factual dispute, the district 

court adopted the Airlines’ evidence and granted their 

motion for summary judgment. In its analysis of the parties’ 

arguments, the court failed to consider the evidence in the 

light most favorable to Clarkson. Instead, the court relied 

only on the Airlines’ statistical evidence. This is evident 

from the district court’s repeated references to the Airlines’ 

Reply Statement of Material Facts, including to several facts 

that Clarkson disputes or materially clarifies. Further, as 
CLARKSON V. ALASKA AIRLINES, INC. 19

discussed below, the district court’s review of the statistical 

evidence was tainted by its decision to consider military 

leave categorically.

To conclude that the leaves are incomparable, the district 

court compared the longest military leave (185 days at

Alaska, excluding the 99th percentile, and 70 days at

Horizon, excluding the 95th percentile) with the longest jury 

duty leave (6 days at Alaska and 5 days at Horizon), the 

longest bereavement leave (6 days at Alaska and 3 days at

Horizon), and the longest sick leave (5 days at Alaska and 4 

days at Horizon).

8 But Clarkson presented a different

analysis of the data in his opposition to summary judgment. 

His analysis showed that Alaska pilots took an average of 

3.10 days of short-term military leave, 2.94 days of jury duty 

leave, 2.77 days of bereavement leave, and 2.52 days of sick 

leave.

9 Horizon pilots took an average of 4.23 days of shortterm military leave, 2.66 days of jury duty leave, 2.48 days 

of bereavement leave, and 2.17 days of sick leave.

10 The 

8 The jury duty and bereavement leave data presented by the Airlines 

covers the period between October 2004 and December 2020 for Alaska 

pilots and between October 2008 and December 2020 for Horizon pilots. 

The military leave data described above is from those time periods. The 

sick leave data, however, only covers the period from September 2013 

to December 2020 for Alaska pilots and from February 2010 to 

December 2020 for Horizon pilots. During those periods, the 

comparable longest military leave is 122 days for Alaska pilots 

(excluding the 99th percentile) and 58 days for Horizon pilots (excluding 

the 95th percentile). 

9 Again, because the sick leave data covered a different time period, the 

comparable average short-term military leave from September 2013 to 

December 2020 is 2.50 days for Alaska pilots. 

10 The comparable average short-term military leave from February 2010

to December 2020 is 4.23 days for Horizon pilots. 
20 CLARKSON V. ALASKA AIRLINES, INC.

mode and median days of short-term military leave appear 

even more similar to the mode and median days of nonmilitary leaves. The district court did not mention nor 

discuss Clarkson’s analysis. Nor did the district court 

mention the Airlines’ expert’s finding that the longest shortterm military leave, which is the appropriate comparator,

was 6 days for Alaska pilots and 9 days for Horizon pilots

(excluding the 90th percentiles). Using these statistical 

measures, a reasonable jury could find in Clarkson’s favor.

As noted above, summary judgment is only appropriate 

“where viewing the evidence and the inferences which may 

be drawn therefrom in the light most favorable to the adverse 

party, the movant is clearly entitled to prevail as a matter of 

law.” Sandvik, 609 F.2d at 974 (quoting Smith, 604 F.2d at 

641). Here, the evidence put forth by Clarkson—and by the 

Airlines—could allow a jury to infer that the duration of 

military leave is comparable to the duration of jury duty, 

bereavement, or sick leave. The district court erred in 

concluding otherwise. 

b. Frequency

The district court’s decision is also flawed because it 

treated frequency as an integral part of the duration analysis. 

As the court put it, “frequency is useful in the duration 

analysis.” Clarkson, 2021 WL 2080199 at *5. While it is 

true that the implementing regulation leaves room for courts 

to consider factors besides duration, purpose, and control,

see 20 C.F.R. § 1002.150(b) (“[O]ther factors such as

[purpose and control] should also be considered.” (emphasis 

added)), the factors enumerated in the regulation should be 

weighed most heavily when considering whether two leaves 

are comparable. Cf. Sanders v. City of Newport, 657 F.3d 

772, 780-81 (9th Cir. 2011) (interpreting federal labor statute 
CLARKSON V. ALASKA AIRLINES, INC. 21

“in light of the text of the pertinent DOL regulations”). 

Section 1002.150(b) instructs that duration is the “most 

significant” factor in the comparability analysis, and it does

not mention frequency. See 20 C.F.R. § 1002.150(b). 

Frequency is not encompassed within duration. Rather, the 

two terms convey distinct concepts. Duration is “the time 

during which something exists or lasts.” Merriam-Webster

Dictionary, https://www.merriamwebster.com/dictionary/duration (2022). Frequency is “the 

number of repetitions of a periodic process in a unit of time.”

Merriam-Webster Dictionary, https://www.merriamwebster.com/dictionary/frequency (2022). 

Including frequency in the duration analysis effectively 

undermines the purpose of USERRA.11 Congress intended 

USERRA and its predecessor statutes to protect reservists 

during their “frequent absences from work” with the full 

understanding that those frequent absences could “cause 

considerable inconvenience to an employer.” Monroe, 452 

U.S. at 565. Nevertheless, “Congress has provided . . . that 

employers may not rid themselves of such inconveniences 

and productivity losses by discharging or otherwise 

disadvantaging employee-reservists solely because of their 

military obligations.”12 Id. 

11 This error is especially significant given the “canon that provisions for 

benefits to members of the Armed Services are to be construed in the 

beneficiaries’ favor.” King v. St. Vincent’s Hosp., 502 U.S. 215, 220 n.9 

(1991) (citing Fishgold v. Sullivan Drydock & Repair Corp., 328 U.S. 

275, 285 (1946)).

12 Regulations implementing other provisions of USERRA also 

explicitly state that “the timing, frequency, and duration of [a] person’s 

training or service . . . shall not be a basis for denying protection.” 38 

U.S.C. § 4312(h) (emphasis added). 
22 CLARKSON V. ALASKA AIRLINES, INC.

In justifying the use of frequency, the Airlines rely on the 

very rationale that Congress sought to prohibit: “The fact 

that military duty leave happens much more frequently . . .

than, say, jury duty leave, means that providing paid military 

leave is substantially more costly and burdensome to 

operations than providing paid jury duty leave.” But 

Congress enacted USERRA to “prohibit discrimination 

against persons because of their service in the uniformed 

services,” 38 U.S.C. § 4301, regardless of whether those 

anti-discrimination protections increase employers’ costs 

and burdens. See S. Rep. No. 90-1477, at 1 (explaining the 

statute was intended to protect reservists who were 

discriminated against because of frequent obligations).

The Airlines also attempt to justify the use of frequency

by arguing that “frequency is highly relevant in this case due 

to the peculiar military leave patterns unique to pilots,” who

allegedly take more frequent leaves than other military 

reservists. But USERRA is no less protective of pilots than 

of any other military reservist. 

The Airlines’ (and amicus’s) policy arguments that pilots 

will use their frequent military duties to intentionally create 

conflicts to garner double pay, or that airlines will eliminate 

benefits such as paid bereavement leave or paid jury duty 

leave to avoid paying for military leave, are not compelling. 

The Airlines are only required to provide equal treatment, 

not preferential treatment, to employees taking military 

leave. Thus, if the employer only provides three days of paid 

bereavement leave per year or only offers the difference in 

pay between the employee’s salary and the compensation for 

jury duty (as Horizon does), that is all the employer would

be required to provide to the servicemember. We are thus 

unpersuaded by the Airlines’ arguments that a ruling in 
CLARKSON V. ALASKA AIRLINES, INC. 23

Clarkson’s favor would drastically increase costs or 

convince employers to cease offering other paid leaves. 

2. Purpose 

In considering the purpose factor, the district court found 

that “the evidence supports [the Airlines’] position that a 

significant purpose of military leave under the CBAs is to 

allow employees to pursue parallel careers.” Clarkson, 2021

WL 2080199 at *7. By accepting this position, the district 

court rejected Clarkson’s evidence demonstrating that the 

primary purpose of military leave is to perform a civic duty 

and public service. 

Clarkson’s argument is both intuitive and well-supported 

by the record. In his deposition, Clarkson explained that he 

joined the military “to serve.” Alaska representatives also 

repeatedly acknowledged in their depositions and answers to 

interrogatories that public service is a primary purpose of 

military leave. Nonetheless, the Airlines attempt to 

undermine Clarkson’s testimony by pointing to a single 

question and answer from Clarkson’s deposition:

Q: Would you consider it accurate to 

describe military service for Horizon 

pilots as a second career?

A: I don’t know if we could consider it a 

second career. I would say parallel 

career. 

The district court, however, may not judge credibility, 

weigh the evidence, or resolve factual disputes at summary 

judgment. See Anderson, 477 U.S. at 255. The court thus

erred when it held that there are no genuine disputes about
24 CLARKSON V. ALASKA AIRLINES, INC.

the purpose of military leave.

13 It is for the jury to determine 

how much weight to give to the evidence presented about the 

purpose of military leave. 

3. Control 

Finally, the district court found that “pilots have a greater 

degree of control over their ability to take military leave and 

schedule around such leave” than employees taking nonmilitary leaves. Clarkson, 2021 WL 2080199 at *8. In so 

finding, the district court again accepted the Airlines’ factual 

contentions and ignored Clarkson’s factual presentation. 

Given the record evidence, however, a reasonable jury could 

find that pilots do not have significantly more control over 

military duty than they do over other types of leave. 

At both Airlines, pilots bid on their monthly schedules in 

advance and must provide notice of known absences, 

including scheduled military duty, at the time of bidding. 

The scheduling systems are designed to schedule pilots to 

avoid these absences, but conflicts can still occur because 

bidding takes place by seniority. To avoid conflicts after the 

schedules are released, pilots can trade trips with other pilots 

on a voluntary basis (with some limitations) and pick up or 

drop trips (with approval). The parties agree about this basic 

process. They also agree that when a pilot is in the military, 

his or her military service is involuntary. 

The parties disagree, however, about the level of control 

that pilots have to schedule their military duty so that it does 

13 The district court’s conclusion that the purpose of military leave is to 

promote pilots’ own individual interests in a “parallel career” makes 

little sense when military leave is protected by USERRA, which 

Congress enacted explicitly to encourage public service in the military. 

See 38 U.S.C. § 4301. 
CLARKSON V. ALASKA AIRLINES, INC. 25

not conflict with their work schedules at the Airlines. The 

Airlines contend that pilots have “tremendous” flexibility to 

schedule their military service, citing the testimony of 

Ronald Limes, Alaska’s Base Chief Pilot and former Air 

Force reservist.14 In his deposition, Mr. Limes explained 

that as a commander in the reserves, he had “very little” 

flexibility, but as a rank-and-file servicemember, he had 

“tremendous” flexibility to schedule squadron trainings on 

weekends. Clarkson maintains that pilots’ control over 

military duty, especially duties beyond those squadron 

trainings, is more limited. Pilots can work with their military 

schedulers to resolve conflicts, but the ability to reschedule 

military duty depends on many factors including the pilot’s 

training requirements, military needs, and the availability of 

opportunities to engage in specific kinds of training. 

Clarkson also argues that many of the leaves at issue in this 

case were unknown to pilots more than a few weeks in 

advance, rendering pilots’ control over the scheduling 

process irrelevant. In his deposition, Clarkson explained that 

predetermined monthly military schedules would often 

change with little notice. Only the drill weekends, which 

were set annually by the governor, were unlikely to change. 

Given this factual record, the district court erred in 

finding that “[t]o the extent there is any scheduling conflict, 

pilots can . . . work with the bidding system and other pilots 

to ensure their flight schedules for [the Airlines] 

14 The Airlines also argue that the “most pointed evidence” comes from 

Captain James Meldrum, an Alaska pilot who refused to sign a 

declaration stating: “Even if a pilot volunteers for military duty it is the 

military, not the pilot, who dictates the time and duration of that leave.” 

However, in his deposition, Captain Meldrum explained it is only his 

“belief” that military pilots have control; he has never been in the 

military himself. 
26 CLARKSON V. ALASKA AIRLINES, INC.

accommodate their military leave schedules.” Clarkson, 

2021 WL 2080199 at *8. The evidence shows that pilots can 

try to trade shifts with other pilots and that pilots can try to 

work with their military scheduler to rearrange their duty 

periods.15 A jury could reasonably conclude that because of 

last minute assignments, pilots do not have enough control 

over their schedules to prevent conflicts. A jury could also 

find that pilots’ level of control over their military duty is 

comparable to their level of control over other types of

leaves. For instance, pilots receive advance notice of jury 

duty and have some flexibility to reschedule it. Pilots can 

also use sick leave for pre-scheduled appointments or 

procedures. These comparability determinations are for the 

jury to make, not the court.

16 

15 USERRA’s legislative history addresses employees’ ability to

reschedule work, as reflected in the House Report on the bill that became 

§ 4316(b)(1): 

[T]o the extent the employer policy or practice varies 

among various types of non-military leaves of 

absence, the most favorable treatment accorded any 

particular leave would also be accorded the military 

leave . . . . Thus, for example, an employer cannot 

require servicemembers to reschedule their work week 

because of a conflict with reserve or National Guard 

duty, unless all other employees who miss work are 

required to reschedule their work. 

H.R. Rep. 103-65, pt. 1, at 33-34 (1993) (citations omitted); see also 

Rogers, 392 F.3d at 767-68 (citing the House Report). 

16 Clarkson also argues that because military leave is involuntary, the 

“control” factor must come out in his favor. Clarkson relies on 

Waltermyer, which explained that military leave is comparable to jury 

duty leave, bereavement leave, and sick leave because all such leaves 

signaled “lack of choice by the employees.” 804 F.3d at 825. But, in
CLARKSON V. ALASKA AIRLINES, INC. 27

* * *

As explained above, the district court improperly 

resolved factual disputes as to each factor in the 

comparability analysis in order to grant summary judgment. 

Comparability is fundamentally an issue for the jury, and 

where reasonable jurors could return a verdict in favor of the 

nonmoving party, factual disputes must be resolved by a 

jury. See, e.g., Reynaga, 847 F.3d at 685 (citations omitted). 

Here, Clarkson has presented persuasive evidence in support 

of his claim. We therefore reverse the grant of summary 

judgment and remand for further proceedings consistent 

with this opinion. 

C. Pay During Leave 

Finally, the Airlines argue that “pay during leave” is not 

a standalone benefit that they provide under their CBAs to 

any employee on leave, rendering Clarkson’s claim moot 

even if short-term military leave is comparable to another 

type of leave. Because the district court found that military 

leave was not comparable to any other leaves, it did not 

address this issue and “decline[d] to adopt a specific 

interpretation of the ‘rights and benefits’ definition.” 

Clarkson, 2021 WL 2080199 at *3. Although our sister 

circuits have addressed this issue, see Travers, 8 F.4th at

199; White, 987 F.3d at 619, we remand for the district court 

Waltermyer, the court concluded that: “Particularly important is the fact 

that the guardsmen have no individual voice in selecting the weeks they 

will be on active duty.” Id. Here, the Airlines have presented evidence

to demonstrate that pilots may have some “voice in selecting” their

schedules. The governing regulation also clearly states that the factor to 

consider is “the ability of the employee to choose when to take the 

leave,” 20 C.F.R. § 1002.150(b), not whether the leave is voluntary.
28 CLARKSON V. ALASKA AIRLINES, INC.

to consider the “pay during leave” issue in the first instance. 

CONCLUSION

For the foregoing reasons, we reverse the district court’s 

grant of summary judgment to the Airlines. On remand, the 

district court should consider the “pay during leave” issue in 

the first instance. 

REVERSED AND REMANDED.