I am using online check-in for a one-way flight from the United States to Mexico with American Airlines. I am not a US Citizen, but I am a US resident.
During online check-in, it asks "Country of Residence - Select the country / region you live in currently" and I enter the United States.
It then asks for my "Green Card or US Visa - Only enter documents you're using for this trip." And also "Address while in the U.S. - Enter a local address if you're staying in the U.S."
I am not allowed to proceed unless I enter this information. Why do I need to enter my green card and address in the United States, for a one-way trip from the US to Mexico?
If I change my country of residence to Canada, then I don't need to enter my US Green Card or address in the United States, however this is not truthful.
Update : I decided to not use online check-in and checked in using the American Airlines kiosk at the airport. I only needed to scan my Canadian passport, and it printed my boarding pass, and now I'm in Mexico. I never needed to enter my green card or US address at the kiosk, and I never had to interact with a gate agent.