I am PhD student and would like participate a conference in the United States. I have been granted a partial travel grant. But it has a condition that I should travel with a US flag carrier. The funding letter has the following exact sentence:

Please note that our funding through the US National Science Foundation requires that the air carrier must be a US flag air carrier to be eligible for reimbursement.

I don't understand this clearly. Does it mean a airline belonging to a USA company? Or does it mean any airline of any country certified by the USA?

I got the following list of airlines from this website:

  1. Airtran Airways (FL)
  2. Alaska Airlines (AS)
  3. American Airlines (AA)
  4. Delta Airlines (DL)
  5. Frontier Airlines (F9)
  6. Hawaiian Airlines (HA)
  7. Southwest Airlines (WN)
  8. Spirit Airlines (NK)
  9. United Airlines (UA)

For all the above airlines the ticket fare is extremely high. However, I found some dual connections such as "Iberia-American" (ticket sold by American Airlines), "American-British Airways" (ticket sold by British Airways), or "Delta-Virgin Atlantic" etc. In these dual connection, the ticket price is comparatively low.

Are these 3 dual connection considered as US flag carriers? Are there more US flag airlines except the above 10 lists?

  • 10
    The USA has no flag carrier. Pan Am was at some point the de facto USA flag carrier for international flights but I'm not sure it it was ever the flag carrier de jure.
    – randomhead
    May 17, 2022 at 15:09
  • 3
    Did you perhaps mean, rather than flag carrier (which is a very specific and often exclusionary term, i.e. there is only one per country in most cases), that you have to fly on an airline registered in as being based in the USA (i.e. their aircraft generally use N-number registrations and the airline follows FAA regulations)?
    – randomhead
    May 17, 2022 at 15:17
  • 1
    @randomhead, the grant letter simply says 'US flag carrier'
    – MAS
    May 17, 2022 at 15:19
  • 34
    I suggest to contact person giving grant to clarify the issue. No random guy on internet can assure you of outcome.
    – vasin1987
    May 17, 2022 at 17:09
  • 20
    The phrase "flag carrier" is imprecise, and its meaning has changed over the years. The Wikipedia article will give you the background. Because the words are imprecise, the comment of vasin1987 above is correct: you need to find out what the funder wants, and do that. May 17, 2022 at 19:42

4 Answers 4


Your source refers to the Fly America Act. That act is explained in more detail on the GSA website. A real simplistic answer to your question is that a US “flag carrier” is any airline certificated and based in the US that conducts operations to and/or from other nations — IOW, an international airline certificated and based in the United States. That’s not the official definition, but it fits.

  • 2
    The GSA website you linked to has a list of every airline that the GSA considers a “US flag carrier” for the purposes of the FAA as of March 20, 2022: transportation.gov/sites/dot.gov/files/2022-03/…
    – Gaurav
    May 18, 2022 at 15:57
  • @Gaurav That list contains flag carriers, sure, but not only flag carriers. Did you look at the list?
    – afwings
    May 18, 2022 at 16:04
  • "an international airline": it must be a US-based international airline.
    – phoog
    May 18, 2022 at 16:41
  • @phoog exactly. “International air transportation means transportation by air between [one country] and a place outside [that country]…” (lawinsider.com/dictionary/international-air-transportation). “That country” in the case of this question and answer is the United States. Therefore, an “international airline” is an airline engaged in international air transportation. Implied in my answer is that the airline is certificated in the United States, but I changed my answer to include that fact.
    – afwings
    May 18, 2022 at 16:56
  • 3
    @afwings it won't be obvious to many readers that an airline can't be "certificated" in multiple countries. They might reasonably assume, for example, that "certificated in the US" means "authorized to operate commercial flights in the US." Such a reader, therefore, would assume that "an international airline" or even "an international airline certificated in the United States" includes companies such as Lufthansa and Ethiopian, whereas the very point of the act is to exclude such airlines.
    – phoog
    May 18, 2022 at 18:16

I think part of the confusion here arises from conflating "U.S. flag air carrier" with "U.S. flag carrier," which are two entirely different things.

What is a "Flag Carrier?"

A country's "flag carrier," is basically the either official or unofficial "national carrier" of a particular country. For example, Air France for France, KLM for The Netherlands, Lufthansa for Germany, etc. The U.S. does not have a flag carrier, though many decades ago (mostly during and before the 1960s) Pan Am was sort of an unofficial one. A country having a "flag carrier" is mostly a matter of national prestige, but can also be seen as a matter of national security (both military and economic) in the form of ensuring a country can maintain international air service under its own control.

For example, countries maintaining a "flag carrier" for national prestige is the main reason that there are still lots of different major international airlines in Europe (typically one per country,) even though nowadays almost all of them are owned by one of three companies in practice (IAG, AF/KLM, or Lufthansa Group.) The U.S. instead has 3 major international airlines (and a few other smaller ones,) none of which hold any special legal status compared to the others, so there is no "flag carrier" of the United States.

What is a "U.S. Flag Air Carrier?"

What they mean by "U.S. flag air carrier" for the purpose of the Fly America Act, though, is something completely different. Specifically, it means an air carrier that is "flagged" in the U.S. This means that the air carrier received its operating certificate from the U.S. FAA (which, in practice, generally means that the airline is based in the U.S. and typically also that their aircraft are registered in the U.S.) The U.S. Department of Transportation maintains a list of U.S. certificated air carriers on their website. Basically, though, the idea is that you must travel on an American airline unless that's not possible or your travel qualifies for one of the exceptions listed on the General Services Administration's website.

As far as the question about tickets operated by multiple carriers, GSA's website does address that part also:

Occasionally, two or more airlines will "codeshare" a flight by publishing and marketing the same flight under their own airline designators and flight numbers. You can purchase a seat on each airline’s designator and flight number, but the flight is only operated by one of the cooperating airlines. To comply with Fly America regulations, you must purchase the flight via the U.S. airline’s designator and flight number if the flight is shared between a U.S. and a foreign airline.

Note that there's a difference between merely purchasing a ticket sold by a U.S.-flagged airline and purchasing an actual codeshare. The important part here is the flight numbers that appear on the ticket. For example, if American Airlines sells a flight with an AA-coded flight number (e.g. AA6939,) that's ok even if the flight is actually operated by one of their partner airlines, such as British Airways. However, if the flight is sold to you by American Airlines, but with the flight numbers of one of their partner airlines (e.g. BA0178,) then that does not qualify, even though the flight is sold by American.

  • 3
    This is quite possibly the stupidest thing I've ever seen. Needlessly confusing, and with a loophole big enough to fly a plane through. Allowing codeshares operated by foreign airlines surely defeats the entire purpose of the act. How very American of us.
    – A. R.
    May 19, 2022 at 18:36
  • 4
    @AndrewRay Welcome to intersection of the fun worlds of airline fare marketing and government protectionism! It combines all the modernity of cutting-edge 1950s airline fare marketing rules with government economic and transportation policy straight out of the 1800s!
    – reirab
    May 19, 2022 at 22:19

As mentioned in other answers, the source of US government grant funding may stipulate choice of a carrier according to the Fly America Act.

The Act specifies conditions where exceptions can be made - for example there is not a suitable US carrier, or it would take too long. But, as it says:

Note: Ticket cost and convenience are NOT exceptions to the Fly America Act.

However, the Act looks at the issuing carrier rather than the operating carrier. So it is fine to buy a ticket from American Airlines that codeshares onto a British Airways flight, but not the same flight bought from BA directly, nor for an AA flight ticketed by BA.

When searching for suitable flights you often have to be creative about codeshares or about stopovers. Using an advanced flight search (eg Google Flights or Matrix) can be helpful here.

Also things that aren't 'flights' aren't covered - such as trains and ships. Sometimes it can work out to fly into somewhere and then take a train for the onward journey.

  • 1
    "Convenience" per se isn't an exception, but there are some...convenience-related exceptions if not funded by the DOD*. You don't have to use the American carrier if it doubles the flight time (flight < 3 hrs), extends travel by 24 hrs, or requires 2+ more or a long (4 hr) foreign layovers. May 18, 2022 at 19:54

A Flag-Carrier is a transport company that is registered as such in the given country (in this case the United States). They get preferential treatment by the government, and in many cases that includes things like being eligible for certain grants - especially when those grant monies come from the likes of the NSF and whatnot.

Your cited source notes that the Fly America Act restrictions are waived if you're flying to an EU member state, and are doing so aboard a flag-carrier for that state. So that's also an option, and that would meant that partnership routes like Iberian-American are valid... if you're going to Spain. Delta-Virgin would be legit to the U.K.

When in doubt check with your department's compliance folks before you book.

  • 5
    Both Wikipedia and gsa.gov put the emphasis on "U.S. flag", i.e. American, and Wikipedia says "not to be confused with flag carriers". Might be helpful.
    – ymb1
    May 17, 2022 at 15:36
  • 2
    The UK isn't in the EU anymore, so it's not covered by that exception. You shouldn't have any trouble getting a DL codeshare for Virgin, but you wouldn't be able to use British Airways etc. unless there's another exception
    – jdouglas
    May 17, 2022 at 18:50
  • The USA does not have a "flag carrier." "U.S. flag air carrier" for purposes of the Fly America Act means something completely different - namely, that the airline is registered in the U.S.
    – reirab
    May 18, 2022 at 17:01

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .