The Fly America Act, codified at 49 U.S.C. § 40118, requires anyone whose airfare is paid with federal funds to fly on a U.S. flag air carrier whenever one is available. It covers passengers and cargo, domestic and international trips, and applies whether the money comes from a federal salary, a contract, or a grant. Booking a foreign airline without a valid exception means the government will not reimburse the ticket, and in some cases will recover money already paid. Several treaty-based and practical exceptions exist, but each one has to be documented at the time you book.
Who Has to Follow the Rule
The Act is not limited to federal employees on official business. Anyone whose travel is funded with federal money must comply, including:
- Federal employees and their dependents, whether the trip is a conference, a permanent change of station, or any other government purpose.
- Consultants, contractors, and grantees, if the contract or grant budget pays for the flight.
- Any other traveler whose airfare comes from federal funds, including participants in federally funded programs.
University researchers trip over this constantly. A lab running on an NIH, NSF, or DOE grant is bound by the same rules that bind a federal employee. The funding source controls, not the traveler’s employer.
What Counts as a U.S. Flag Air Carrier
A U.S. flag air carrier is an airline holding a certificate of public convenience and necessity under 49 U.S.C. § 41102, which limits the designation to airlines that qualify as U.S. citizens under aviation law. The major domestic airlines all qualify. Foreign airlines never do, even when they operate flights inside the United States.
Code-share flights are where compliance gets subtle. Many international routes are marketed by one airline and physically operated by another. A flight sold as United but flown by Lufthansa can still satisfy the Act, provided the ticket is issued under the U.S. carrier’s designator code and flight number. What matters is the code on the ticket, not the logo on the aircraft. If you book a code-share, confirm that the itinerary and receipt show the U.S. carrier’s two-letter designator.
Price and convenience are not exceptions. A foreign carrier offering a cheaper fare or a friendlier schedule does not justify skipping a U.S. airline. The GSA has stated plainly that neither cost nor convenience opens the door to a foreign booking.
Check the GSA City-Pair Program First
Before looking at exceptions, check whether your route is covered by a GSA city-pair contract fare. GSA negotiates discounted government fares with U.S. airlines for specific city pairs, and those fares generally include benefits like no cancellation fees. The fare finder tool on the GSA website will show any contracted fare for your origin and destination in the current fiscal year.
This step is not optional planning. Several Open Skies exceptions shut off entirely when a city-pair contract fare covers your route, and skipping the check is one of the most common compliance mistakes.
Open Skies Agreement Exceptions
The United States has Open Skies aviation treaties with more than 100 countries, but only four of them meet the Fly America Act’s requirements for government-funded travel. The qualifying agreements are with:
- The European Union (28 countries including Austria, Belgium, France, Germany, Ireland, Italy, the Netherlands, Spain, and Sweden, plus Iceland and Norway).
- Australia.
- Switzerland.
- Japan.
The EU agreement is the broadest. It generally permits use of EU-member-country airlines on routes between the United States and EU member states, and between two points outside the United States. The Australia, Switzerland, and Japan agreements are narrower: they allow that country’s airlines for travel between the United States and that specific country, and only when no GSA city-pair contract fare covers the route.
The United Kingdom After Brexit
Since January 1, 2021, the United Kingdom is no longer part of the EU, and the EU Open Skies Agreement no longer covers UK airlines such as British Airways or Virgin Atlantic. For a trip between the United States and the United Kingdom, you must use a U.S. flag carrier unless another Fly America Act exception applies. One workaround remains: the EU agreement can still cover U.S.-to-UK travel if the itinerary routes through an EU member country.
Department of Defense Travel
The Open Skies exceptions do not apply to travel funded by the Department of Defense or any military department. DoD-funded trips must use a U.S. flag carrier regardless of any Open Skies agreement. The standard exceptions for unavailability, timing, medical need, and involuntary rerouting still apply.
Practical Exceptions Under 41 CFR 301-10.135
Federal regulations recognize situations where using a foreign airline is a practical necessity.
No U.S. Carrier Service Available
If no U.S. flag carrier flies a particular leg of your route, you may use a foreign airline for that segment, but only to the nearest interchange point where you can connect back to a U.S. carrier. The same rule applies when every seat in your authorized class of service on a U.S. carrier is sold out and a foreign airline has availability in that class.
Unreasonable Travel Time
You may use a foreign carrier when routing through a U.S. airline would:
- Extend your total travel time by six hours or more.
- Require a connecting wait of four hours or more at an overseas interchange point.
- Increase the number of aircraft changes you make outside the United States by two or more.
Two additional thresholds apply to specific situations. When the total flight time from origin to destination is under three hours and using a U.S. carrier would double your travel time, a foreign carrier is permitted. For nonstop flights between the United States and another country, if a U.S. carrier offers nonstop service but using it would extend your travel time by 24 hours or more, including delays at the origin, you may take a foreign airline instead.
Medical and Safety Reasons
Foreign carrier use is permitted for medical reasons, including situations where reducing connections or potential delays is necessary for a traveler receiving treatment. Safety-related exceptions require a case-by-case agency determination and written approval. Where there is a specific threat against U.S. flag carriers on a particular route, the exception must be supported by a travel advisory from the FAA and the State Department.
Involuntary Rerouting
If a U.S. carrier reroutes you onto a foreign airline because of weather, mechanical issues, or scheduling problems, the Act does not penalize you. The Government Accountability Office has held that the traveler meets the obligation as long as the original booking was on a U.S. carrier and the rerouting happened through no fault of the traveler. Keep documentation from the airline showing the original booking and the reason for the change.
Waiver Documentation
To get reimbursed for a foreign carrier flight, your travel claim needs three items:
- A completed and signed agency exception form. Most federal agencies and federally funded universities have their own version of the Fly America Act waiver checklist, and it will ask you to identify which specific exception applies.
- A detailed travel itinerary from a travel agent or online booking service, showing all flight numbers, departure and arrival times, and routing for every leg.
- Search results from the time of booking. Screenshots or printouts from a booking site that show what flights were available at the moment you made the reservation are the evidence that a U.S. carrier was genuinely unavailable or that the exception fit.
Gather this at the time of booking, not after the trip. Reconstructing flight availability weeks later is difficult, and auditors are not sympathetic to incomplete records.
What Happens if You Do Not Comply
If you fly a foreign carrier without a valid exception and proper documentation, the expense is yours. The GAO has held that agencies must disallow any expenditure on a foreign carrier unless the traveler can prove the foreign service was necessary. For grant-funded travelers, that cost typically falls on the institution. A missing waiver form or an exception that does not actually fit your routing leads to a flat denial, and agencies have little discretion to override that result.
Cargo and the Pet Carve-Out
The Act also reaches property. Any air shipment paid for with federal funds, including lab equipment, research samples, and household goods during a government-funded relocation, must go on a U.S. flag carrier or a qualifying code-share. The Open Skies exceptions apply to cargo on the same terms as passengers, and they remain unavailable for DoD-funded shipments.
One narrow statutory carve-out covers military members and DoD civilian employees traveling with pets. If no U.S. carrier is willing and able to transport the traveler along with up to three cats or dogs, a foreign carrier may be used, and the traveler covers any difference between the foreign fare and what the U.S. carrier would have charged.