New Jersey ? A man walked through a screening checkpoint exit into the secure side of a terminal at one of the nation’s busiest airports on Sunday night, and flights were grounded for hours and passengers had to be re-screened while air safety officials searched for him.

Airline passengers were allowed to begin boarding their planes at Newark Liberty International Airport about six hours after the man was seen bypassing security.

The man walked down an exit lane at Terminal C about 5:30 p.m., Transportation Security Administration spokeswoman Ann Davis said, and screening was halted while authorities looked at surveillance tapes to try to identify him.

The terminal was searched thoroughly to make sure no dangerous objects were in it before the boarding began, the TSA said. The man wasn’t found, but the TSA said its re-screening effort ensured every passenger was fully screened.