At the largest terminal at New York’s John F. Kennedy International Airport on one of the busiest travel days of the year, security lapses enabled an unticketed passenger to board a plane to Paris in a shocking breach that one aviation expert said should serve as a “wake-up call” for the airline industry.

A stowaway who made it all the way from New York to Paris on a flight is expected to be brought back to the U.S. Wednesday afternoon escorted by French security officials.