[vijayr]

How does it work for foreigners (aka "aliens" - what a weird term) living here?

[callahad]

Permanent resident cards, foreign passports, and many other documents are accepted in addition to Real IDs: https://www.tsa.gov/travel/security-screening/identification

[mikeash]

Note that this use is the original meaning of "alien." The contemporary meaning of "extraterrestrial" is a recent mutation of it.