What If I Don't Have My Real ID or Passport?

Passengers who present a state-issued identification that is not REAL ID compliant at TSA checkpoints and who do not have another acceptable alternative form of ID will be notified of their non-compliance. They may be directed to a separate area and receive additional screening. This includes TSA Pre-Check passengers.

No Real ID?

https://www.tsa.gov/real-id/real-id-faqs