How to Travel on Airplanes
Flying Domestically in the United States

Undocumented students, youth, young adults and other immigrants are legally allowed to fly domestically within the United States.
Undocumented immigrants regularly fly on airplanes, and while there is a risk of being turned over to ICE, it usually only occurs when: (a) immigrants used expired documentation (like expired Mexican Passports); or (b) more recently, Mexican Matriculas (though this is rare).
Upon obtaining your ticket and / or crossing the security checkpoint you can:
- Present a Mexican Passport -- How to get a Mexican Passport
The Mexican Passport is considered a valid form of identification and will alow you to proceed through security normally. TSA explicity states this in their "Acceptable Documents" PDF.
Until further notice, you should avoid flying with the the Mexican Matricula. There have been reports of undocumented students being stopped and turned over to ICE for using a Matricula. For more information click here.
Ideally, you should show either your passport when flying. There is absolutely no risk involved. Personally, I flew over two dozen times across the country in the span of four years using my passport.
Flying Internationally
Undocumented immigrants should not, under any circumstances, fly internationally.
Without a valid U.S. Passport or visa you will not be able to re-enter the country legally. Upon leaving you also trigger a ten year re-entry bar (the bar could be more or less depending on how long you've resided in the United States without status) which prevents you from legally re-entering the country.