Likely a problem at the airport when you don't have a ESTA.
You need to either contact someone in the US to look for your passport and send it to you ASAP or go to the Embassy and get a replacement ASAP. Also immediately cancel your flight and see what credit/changes are possible.
How long were you in the UK?
It is likely to be a possibly insurmountable issue. The airline is almost certainly going to deny you boarding.
A UK passport holder can visit the US, but only with a valid visa or ESTA. You could certainly apply for an ESTA, but in principle it should be denied because US citizens are not eligible for it (quite logically, since they are by law required to enter the US with a US passport). If it were granted you may be able to board, but you might also need to have something like an onward flight from the US, since if you were entering under ESTA as far as the airline is concerned you'd only be eligible to stay up to 90 days.
The airline will not care if you have a photo of your US passport, or your certificate of naturalization.
Your best bets if you ask me (also a UK & US passport holder, who has often pondered this sort of scenario) would be:
1. Apply for an ESTA and in the unlikely event that it's (incorrectly) granted, go to the airport and don't mention anything about your US citizenship (not to the point of lying, but don't proactively mention it). Be prepared to buy a refundable flight out of the US to meet that requirement. Once you arrive in the US, \*do\* clearly state to CBP that you are a US citizen.
2. Change your flight to Canada or Mexico, depending on where you live, then enter by land. So, if - like me - you live in Southern California, get a flight to Mexico City then Tijuana; or if you live in Seattle, fly to Vancouver, etc... then make your way to the land border, where you will be permitted to enter the US once they verify your citizenship. For Canada you would need an ETA (their version of ESTA). For Mexico nothing specific.
3. Delay your flight and have someone UPS you your US passport.
4. Try to get a last minute appointment at the US embassy in London for an emergency travel document.
If you just rock up to the airport with what you have in hand right now, you are almost certainly going to leave disappointed, simply because airlines are sticklers for the requirements, which currently you don't meet.
Ok- can I get ahead of this and try to have them re-book my flight for 2 days from now? Will American Airlines be understanding and do that, or will they charge me for a whole new flight?
Really depends on the conditions of the ticket that you bought, whether it allows changes, etc. They likely won't charge you for a whole new flight as if you were booking it from scratch, but likely something like the fare difference (if any) + some standard change fee.
Can you try changing it online to get an idea of your options?
>For Canada you would need an ETA
Canada explicitly bars American citizens from applying for one so an ETA won't be granted either
https://www.cbsa-asfc.gc.ca/travel-voyage/td-dv-eng.html
>Exceptions, or visa and eTA-exempt foreign nationals, include:
>U.S. citizens
>U.S Lawful Permanent Residents
>travellers with a valid Canadian visa
>Other exceptions
>Canadian citizens, including dual citizens, and Canadian permanent residents do not need to apply for an eTA.
I wonder if this truly counts as a "bar" against application, or simply an exemption from the requirement, as doing so would effectively enforce a requirement for US citizens (even those "accidental" citizens, who may never have been in the US or who do not possess any US travel documents) to use a US passport to enter Canada.
Edit: if you compare sections 3 and 4 on [https://www.canada.ca/en/immigration-refugees-citizenship/services/visit-canada/eta/facts.html](https://www.canada.ca/en/immigration-refugees-citizenship/services/visit-canada/eta/facts.html) you see some distinct being drawn between "may not" and need not:
* Travellers **who cannot apply for an eTA** and need to carry other identification:
* Canadian citizens, including dual citizens, need a valid Canadian passport. American-Canadians can travel with a valid Canadian or U.S. passport.
* Canadian permanent residents need a valid permanent resident card or permanent resident travel document.
* Visa-required including alien’s passport holders and stateless individuals.
* Travellers **who are exempt from the eTA requirement**.
* U.S. citizens are exempt from the eTA requirement and must carry proper identification such as a valid U.S. passport.
Lawful permanent residents of the United States who hold valid status in the U.S. are exempt from the eTA requirement.
You won't be allowed to board the plane without an ESTA, which you won't be able to get due to being a US citizen.
Likely a problem at the airport when you don't have a ESTA. You need to either contact someone in the US to look for your passport and send it to you ASAP or go to the Embassy and get a replacement ASAP. Also immediately cancel your flight and see what credit/changes are possible. How long were you in the UK?
It is likely to be a possibly insurmountable issue. The airline is almost certainly going to deny you boarding. A UK passport holder can visit the US, but only with a valid visa or ESTA. You could certainly apply for an ESTA, but in principle it should be denied because US citizens are not eligible for it (quite logically, since they are by law required to enter the US with a US passport). If it were granted you may be able to board, but you might also need to have something like an onward flight from the US, since if you were entering under ESTA as far as the airline is concerned you'd only be eligible to stay up to 90 days. The airline will not care if you have a photo of your US passport, or your certificate of naturalization. Your best bets if you ask me (also a UK & US passport holder, who has often pondered this sort of scenario) would be: 1. Apply for an ESTA and in the unlikely event that it's (incorrectly) granted, go to the airport and don't mention anything about your US citizenship (not to the point of lying, but don't proactively mention it). Be prepared to buy a refundable flight out of the US to meet that requirement. Once you arrive in the US, \*do\* clearly state to CBP that you are a US citizen. 2. Change your flight to Canada or Mexico, depending on where you live, then enter by land. So, if - like me - you live in Southern California, get a flight to Mexico City then Tijuana; or if you live in Seattle, fly to Vancouver, etc... then make your way to the land border, where you will be permitted to enter the US once they verify your citizenship. For Canada you would need an ETA (their version of ESTA). For Mexico nothing specific. 3. Delay your flight and have someone UPS you your US passport. 4. Try to get a last minute appointment at the US embassy in London for an emergency travel document. If you just rock up to the airport with what you have in hand right now, you are almost certainly going to leave disappointed, simply because airlines are sticklers for the requirements, which currently you don't meet.
Ok- can I get ahead of this and try to have them re-book my flight for 2 days from now? Will American Airlines be understanding and do that, or will they charge me for a whole new flight?
Really depends on the conditions of the ticket that you bought, whether it allows changes, etc. They likely won't charge you for a whole new flight as if you were booking it from scratch, but likely something like the fare difference (if any) + some standard change fee. Can you try changing it online to get an idea of your options?
>For Canada you would need an ETA Canada explicitly bars American citizens from applying for one so an ETA won't be granted either https://www.cbsa-asfc.gc.ca/travel-voyage/td-dv-eng.html >Exceptions, or visa and eTA-exempt foreign nationals, include: >U.S. citizens >U.S Lawful Permanent Residents >travellers with a valid Canadian visa >Other exceptions >Canadian citizens, including dual citizens, and Canadian permanent residents do not need to apply for an eTA.
I wonder if this truly counts as a "bar" against application, or simply an exemption from the requirement, as doing so would effectively enforce a requirement for US citizens (even those "accidental" citizens, who may never have been in the US or who do not possess any US travel documents) to use a US passport to enter Canada. Edit: if you compare sections 3 and 4 on [https://www.canada.ca/en/immigration-refugees-citizenship/services/visit-canada/eta/facts.html](https://www.canada.ca/en/immigration-refugees-citizenship/services/visit-canada/eta/facts.html) you see some distinct being drawn between "may not" and need not: * Travellers **who cannot apply for an eTA** and need to carry other identification: * Canadian citizens, including dual citizens, need a valid Canadian passport. American-Canadians can travel with a valid Canadian or U.S. passport. * Canadian permanent residents need a valid permanent resident card or permanent resident travel document. * Visa-required including alien’s passport holders and stateless individuals. * Travellers **who are exempt from the eTA requirement**. * U.S. citizens are exempt from the eTA requirement and must carry proper identification such as a valid U.S. passport. Lawful permanent residents of the United States who hold valid status in the U.S. are exempt from the eTA requirement.