Your domestic air travel could be delayed if you don’t have an accepted form of identification at TSA checkpoints come Wednesday, the deadline for “REAL ID.”

The Transportation Security Administration (TSA) said 81 percent of air travelers already present forms of identification that comply with Real ID requirements, which went into effect Wednesday. A

The Real ID Act is now enforced by TSA at U.S. airports for domestic flights, prompting a rush to obtain compliant identification. At Philadelphia International Airport, travelers without a Real ID receive informational flyers from TSA.