This case concerns whether time workers spent traveling on employer-provided transportation to a secure construction site or time spent going through security screening is compensable under the Fair Labor Standards Act (“FLSA”), 29 U.S.C. § 201 et seq. Appellants Percy Bonilla, et al. (“appellants”), plaintiffs in the underlying dispute, appeal the district court’s[*1341] summary judgment order in favor of ap-pellee-defendant, Baker Concrete Construction, Inc. (“appellee”). After careful consideration of the briefs, oral argument, and evidence in the record, we AFFIRM the district court’s order.

I. BACKGROUND

Appellants were construction workers employed by appellee, a subcontractor for the lead contractor Turner-Austin, for the North Terminal project at Miami International Airport (“MIA project”) from approximately November 2001 until March 2003.^[1]

In order to reach their work sites inside the airport, appellants were required to pass through a single security checkpoint to the tarmac and then ride authorized buses or vans to their particular work site. Because FAA regulations prohibit unauthorized vehicles in the secured tarmac area, Turner-Austin provided free buses or vans to transport appellants and other workers from the free employee parking lot to the security gate and on through to each of the separate work sites. Appellants were not required to park at the employee lot, but they were required to enter the facility through the single authorized security entrance and then ride the contractors’ authorized vehicles to the various work sites. The security gate was near other public parking lots and a public bus stop; appellants were free to meet the authorized vehicle at the security gate rather than at the employee parking lot several miles away. Riding Turner-Austin’s authorized vehicles was the only way for the workers to access the construction sites after passing through the security gate.

The employees did not perform any labor while waiting for or riding the vehicles, either at the beginning or end of each work day. No instructions were given by the supervisors nor were any tools carried on the buses because the tools were kept at the work sites. Appellants signed in at the work site and then received their instructions for the day. At the end of the day, appellants would sign out before boarding the bus to leave the airport through the security gate.

Although appellants claim that appellee or Turner-Austin supervisors did work on the vehicles and at the security gate (head counts and general supervision), appellants do not claim that they had any responsibilities or duties before arriving at their respective sites other than to show their identification at the security gate and carry their personal safety equipment, including safety goggles, a hard hat, and work boots. Appellants point to the contractors’ agreement with the airport, the Construction Related Requirements (“CRR”), that requires all employees to display their personal safety equipment as a condition of being transported to the job site. Appel-lee disputes appellants’ claim that there was any evidence that employees were required to carry their personal safety equipment on the bus.

Appellants were not paid by appellee for the time spent riding the buses or vans. There were no allegations that appellee, Turner-Austin, or any representative of appellee ever discussed with appellants whether they would be paid for the time waiting for or riding the authorized buses, nor were there any requests by appellants to be paid for this time.

II. DISCUSSION

We review the district court’s grant of summary judgment de novo. Gibson v. [*1342] RTC, 51 F.3d 1016, 1020 (11th Cir.1995). This appeal presents a question of statutory interpretation. Section 4(a) of the Portal-to-Portal Act, 29 U.S.C. § 254(a), exempts certain activities from compensation under the FLSA, 29 U.S.C. §§ 201 et seq. The question before us is whether appellants’ time spent riding the buses or going through airport security constitutes such an exception. The Act exempts the following activities from compensation:

(1) walking, riding, or traveling to and from the actual place of performance of the principal activity or activities which such employee is employed to perform, and

(2) activities which are preliminary to or postliminary to said principal activity or activities,

which occur either prior to the time on any particular workday at which such employee commences, or subsequent to the time on any particular workday at which he ceases, such principal activity or activities ....

29 U.S.C. § 254(a).^[2]

Under the plain meaning of section 254(a), this case pivots on whether appellants are engaging in any work-related activity before arriving at their work sites inside the airport tarmac. If appellants were merely traveling to their “actual place of performance of the principal activities]” before beginning any work activity, then section 254(a)(1) exempts such traveling from compensation under the FLSA. But, if appellants, by boarding those buses, going through security, or carrying their personal safety equipment, are engaging in work-related activity that is “integral and indispensable” to their work, then any travel afterwards is compensable. IBP, Inc. v. Alvarez, 546 U.S. 21, 37, 126 S.Ct. 514, 525, 163 L.Ed.2d 288 (2005) (“[A]ny activity that is ‘integral and indispensable’ to a ‘principal activity’ is itself a ‘principal activity’ under [29 U.S.C. § 254(a)] of the Portal-to-Portal Act. Moreover, during a continuous workday, any walking time that occurs after the beginning of the employee’s first principal activity is excluded from the scope of the provision, and as a result is covered by the FLSA.”).

a) Travel Claim

The district court found that it is “undisputed that the actual place of performance of the principal activity or activities which [appellee] employed [appellants] to perform was the Project jobsite at MIA’s North Terminal,” and that it “is also undisputed that [appellants] did not perform any work either when waiting for the buses or while they were riding the buses.” We find nothing in the record to contradict this conclusion. As stated above, the parties disagree as to whether appellants were required to carry their personal safety gear on the buses. But we do not find this dispute to be material to the issue at hand because our analysis of the Portal-to-Portal Act would be the same regardless. See Danskine v. Miami Dade Fire Dep’t, 253 F.3d 1288, 1292-93 (11th Cir.2001) (“A factual dispute is genuine only if the evidence is such that a reasonable factfinder could return a verdict for the non-moving party.”) (internal quotations and citation omitted).

The Department of Labor has issued interpretive statements giving examples of non-compensable travel under § 254(a).[*1343] These statements are not promulgated regulations because Congress did not authorize the Secretary of Labor to issue regulations regarding the scope of the exemptions. 29 C.F.R. § 790.1(c); see Gonzales v. Oregon, 546 U.S. 243, 126 S.Ct. 904, 914-15, 163 L.Ed.2d 748 (2006) (“Deference in accordance with Chevron, however, is warranted only when it appears that Congress delegated authority to the agency generally to make rules carrying the force of law, and that the agency interpretation claiming deference was promulgated in the exercise of that authority.”) (citation and quotation omitted).

Here, however, the illustrative examples are persuasive and should be given due deference. See Skidmore v. Swift & Co., 323 U.S. 134, 140, 65 S.Ct. 161, 164, 89 L.Ed. 124 (1944) (“[R]ulings, interpretations and opinions of the Administrator under this Act, while not controlling upon the courts by reason of their authority, do constitute a body of experience and informed judgment to which courts and litigants may properly resort for guidance. The weight of such a judgment in a particular case will depend upon the thoroughness evident in its consideration, the validity of its reasoning, its consistency with earlier and later pronouncements, and all those factors which give it power to persuade, if lacking power to control.”). In this case, the DOL’s interpretation of § 254(a) speaks directly to the issue at hand:

Examples of walking, riding, or traveling which may be performed outside the workday and would normally be considered “preliminary” or “postliminary” activities are (1) walking or riding by an employee between the plant gate and the employee’s lathe, workbench or other actual place of performance of his principal activity or activities; (2) riding on buses between a town and an outlying mine or factory where the employee is employed; and (3) riding on buses or trains from a logging camp to a particular site at which the logging operations are actually being conducted.

29 C.F.R. § 790.7(f).

The plain language of section 254(a)(1) excludes “walking, riding, or traveling to and from the actual place of performance of the principal activity or activities.” The appellants’ claim regarding the time spent on the employer vehicles both before and after the security check point fits squarely within this statutory exception, and the administrative interpretation of the statute also specifically addresses the question of transportation to and from the work site. The fact that the workers were required to ride authorized transportation after the security gate but the transportation to the security gate was optional is not relevant to the outcome of this case because even mandatory travel time is exempted from compensation under the Portal-to-Portal Act. We therefore hold that the time appellants spent traveling on the vehicles both before and after the security check point is exempt from compensation under the FLSA.^[3]

[*1344] b) Security Screening Claim

Unlike the time spent riding the employer vehicles, the time appellants spent going through airport security is not exempted under § 254(a)(1), so we must determine if this security screening is exempted under another provision.^[4] Section 254(a)(2) exempts “activities which are preliminary to or postliminary to said principal activity or activities.” The Supreme Court has interpreted this section to apply when an activity before or after the principal work activity is not an “integral and indispensable part of the principal activities for which covered workmen are employed and are not specifically excluded by Section [254(a)(1)].” Steiner v. Mitchell, 350 U.S. 247, 256, 76 S.Ct. 330, 335, 100 L.Ed. 267 (1956).

The former Fifth Circuit analyzed several factors to determine whether preliminary or postliminary activities are so “integral and indispensable” as to be compensable. Dunlop v. City Elec., Inc., 527 F.2d 394, 398-400 (5th Cir.1976).^[5] The factors to be considered are: (1) whether the activity is required by the employer, (2) whether the activity is necessary for the employee to perform his or her duties, and (3) whether the activity primarily benefits the employer. Id. at 401. In this case, the screening was required by the FAA, and appellee had no discretion as to whether its employees would be screened. See 49 C.F.R. § 1540.17; see also Civil Aviation Security Rules, 67 Fed.Reg. 8340 at 8354 (Feb. 22, 2002). So although the screening was necessary for the employees to perform their work, appellee did not primarily— or even particularly—benefit from the security regime.

Appellants place great weight on the necessity of going through the screening in order to do their jobs. But the “integral and indispensable” test is not a but-for test of causal necessity. “[T]he fact that certain preshift activities are necessary for employees to engage in their principal activities does not mean that those preshift activities are ‘integral and indispensable’ to a ‘principal activity’ under Steiner.” IBP, 546 U.S. at 40-41, 126 S.Ct. at 518. If mere causal necessity was sufficient to constitute a compensable activity, all commuting would be compensable because it is a practical necessity for all workers to travel from their homes to their jobs. If the Portal-to-Portal Act is to have any meaning at all, its terms cannot be swallowed by an all-inclusive definition of “integral and indispensable.”^[6]

In IBP, the Supreme Court addressed whether the time spent waiting to don

[*1345] protective clothing on the employer’s premises before engaging in productive labor was compensable under the Portal-to-Portal Act. IBP, 546 U.S. at 24, 126 S.Ct. at 518. The Court held, in part, that the time workers spent waiting to don protective gear necessary for productive labor was not itself “integral and indispensable” to a “principal activity.” IBP, 546 U.S. at 42, 126 S.Ct. at 528.

This circuit has not interpreted the Portal-to-Portal Act in a published opinion since the Supreme Court decided IBP.7 The statutory language of the exemptions does not allow for a clean analytical distinction between those activities that are “integral and indispensable” and those that are not. But it is clear to us from the Act’s language and history that the activity in question must be work in the benefit of the employer, and that the security screening mandated by the FAA in this case is not compensable work. We therefore hold that the time appellants spent going through the mandatory security screening is not compensable under the FLSA because that screening is not “integral and indispensable” to a principal activity under IBP, Steiner, or Dunlop.

III. CONCLUSION

For the reasons stated above, we AFFIRM the district court’s grant of summary judgment in this case.