After two decades marked by delays, Americans hoping to board an airplane for a domestic flight on Wednesday will need a Real ID.

Travelers without a REAL ID have been assured they will be allowed to fly despite missing Wednesday's deadline but are advised to arrive at their airport early for extra security checks.

REAL ID or other eligible identification is required to board domestic flights at PHL airport, or travelers risk added wait times at TSA checkpoints.

State government offices that issue driver’s licenses and state IDs have seen a significant increase in demand for REAL ID and some have extended their office hours to meet the demand. Some officials have recommended people wait for a while to get REAL ID compliant licenses and cards if they don’t have flight planned in the next few months.

If you've missed the deadline, you don't need to panic. But you should be aware of what that means for your ability to travel, and how to fix it.