With the advent of the Western Hemisphere Travel Initiative, the US introduced passport cards to reduce the burden on US citizens who travel by land or sea to neighboring countries. The card has a much lower cost than a traditional passport ($30 instead of $110).

But these cards are not valid for international flights. A US citizen can use one to drive from Detroit to Toronto, but not to fly. What is the purpose of this restriction?

I should add that I'm interested in the reasons given by politicians, which is why I have asked here on Politics.

  • 1
    A pure speculation. When you fly into US, and approach the border control, the officer knows where you came from (and where have you been) by looking at the passport stamp. The card does not convey this information.
    – user58697
    Jul 14, 2018 at 23:52

2 Answers 2


The State Department FAQ page covering this explains the limited uses for the Passport card as follows:

The passport card was designed for the specific needs of northern and southern U.S. border communities with residents that cross the border frequently by land. The passport book is the only document approved for international travel by air.

Final rule covering this can be found at 72 FR 74169, which includes further explanation of the rulemaking process used, and says:

The passport card was specifically designed to respond to the concerns expressed by border communities in regard to the requirements of WHTI. The passport card is designed specifically to address the unique circumstances of land border crossings and is not intended to be a globally interoperable travel document. Therefore, passport cards will not be designed to meet the International Civil Aviation Organization (ICAO) standards and recommendations for globally interoperable passports.

Because the passport card will be specifically designed to facilitate land and sea border crossings, it is not compatible with the global air environment, which is already set up for passport books. In addition, extending the use of the passport card to the air environment could create confusion with the traveling public should they attempt to use the passport card for travel to a country other than Mexico, Canada or the Caribbean.

The paragraph citing International Civil Aviation Organization standards probably best explains the restriction, but rather than view this as an restriction, it might help to view this as targeted relaxation of rules for residents of the border communities, who prior to WHTI could drive across the border at no cost, with appropriate locally-issued identification. A number of border states, starting with the State of Washington, were able to offer an alternative, the 'enhanced drivers licenses' which homeland security eventually decided to accept. In Washington state, travel to/from Canada via boat is fairly uncommon, which probably explains why the passport cards are also acceptable for "sea" use.

  • Practical example: I can fly in the EU with my Dutch ID card (which is similar to the US passport card), but none of the automatic passport checks work for these cards, so it needs a manual check (most – though not all – of the airline's automatic checkin machines do work though). Also when I went to Iceland (not part of EU, but part of Schengen area) the Icelandic border guard was a bit confused by my ID card, as was the UK official who rescheduled my missed flight a while ago, so additional training is probably also a factor.
    – user11249
    Oct 16, 2018 at 1:25

It likely has to do with expectation of what agents should know. The passport card looks very similar to a driver's license, and is almost certainly less secure or unique than a passport book. When driving to the US from Canada or Mexico, you always face a US Customs agent who will know the exact specifications necessary. When flying, from some airports you go through Customs at the departure country, where the goal is simplification. The passport card in general is less secure than a passport book, and for international flights there is a higher risk factor than for borders some people cross dozens of times a day.

  • 3
    "The passport card in general is less secure than a passport book" Why? Jul 13, 2018 at 19:37
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    Do you have any evidence that this line of reasoning was either (1) actually considered when legislative proposals for the WHTI and passport card were being developed, or (2) offered to the US public as an explanation for the restriction? Also, if we accept (for the sake of argument, if necessary) that the passport card is indeed less secure, why is the lower level of security acceptable at a land border but not for an air traveler? Also, I'm not asking why other countries might not accept passport cards but about why the State department restricts their use.
    – phoog
    Jul 13, 2018 at 19:54
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    Do you have a reference supporting the assertion that passport card RFID technology is less advanced? I would have thought that it, like that of a passport, complies with the ICAO standard.
    – phoog
    Jul 13, 2018 at 19:55
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    @Eremi: that eweek page says that RFID in general is useless for security, not that the one found in passports is significantly better. The passports apparently transmit more RFID data, including the photo, whereas the card just transmits a key that needs to be looked up. It's not at all clear that cloning one RFID is much harder than the other just based on this. My guess is that the actual difference could come from the fact that the on-line access to the database needed for the cards' key[s] isn't widespread. Jul 13, 2018 at 21:27
  • 1
    @Fizz I'm mostly interested in the reasons stated by politicians (which is why I asked here at Politics). Whether the reasons are correct is secondary.
    – phoog
    Jul 13, 2018 at 22:00

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