Authorities in the United States have reviewed airport security footage as they continue to investigate how a woman sneaked on board a Delta Air Lines flight from New York to Paris without a ticket last Tuesday –– one of the busiest travel days of the year.

Last week, a woman managed to sneak onto the Delta flight and get to Paris. She had been held in Charles de Gaulle airport until Saturday.

The woman who snuck onto a New York to Paris Delta flight without a ticket remains in custody in France. Sources say she was removed from her return flight to the United States after she caused a disturbance before takeoff.