US travellers who arrive at airport security without a Real ID-compliant form of identification may face extra checks, delays or be unable to board domestic flights. The change matters because federal enforcement is intended to strengthen identity verification, making it important for passengers to check their documents well before travelling.

A compliant driving licence or state ID usually carries a star marking, although accepted alternatives include a passport and certain federal IDs. Requirements apply to domestic air travel for adults, while rules and possible consequences can vary by airport and the identification presented.