Yet another stowaway managed to board a major airline’s plane – renewing serious questions and concerns about airport safety during the busiest travel season of the year.

A Hawaii-bound Delta Air Lines flight from Seattle-Tacoma International Airport was delayed over two hours on Christmas Eve when a stowaway was discovered by flight attendants just before takeoff, prompting the pilot to make a U-turn on the runway and return to the gate.

The person, who boarded the flight without a ticket, was detected as the plane was preparing to take off for Hawaii on Christmas Eve.