Police say 61-year-old Phillipe Jeannard of La Rochelle, France wore an Air France shirt and had fake credentials identifying him as an Air France crew member.
He initially argued with the gate agent when he couldn't get a seat upgrade.
When he got on the US Airways plane, police say he went right into the cockpit and made himself at home on the jump seat.
"There was conversation between the first officer, a captain. They were talking about the aircraft, he talked as though he was a pilot," said Captain Michael Murphy, Philadelphia Police Department.
They were close to departure when the gate agent, closing the door, noticed Jeannard in the cockpit.
She alerted the crew that he was a ticketed passenger, not a pilot. They called the police and Jeannard was escorted off the plane.
He's charged with criminal trespassing and tampering with records.
Some pilots worry about what might have happened if the intruder had a knife. Starting April 25th, passengers will be allowed to carry small knives.
"Something we're working on our side to prevent. If they pass it through than it's another threat we would have to be aware of," said Captain Justin Stolzfus, Republic Airlines.
Action News asked TSA spokesperson Anne Davis if cockpit doors should be locked during boarding.
She laughed and said a knife wielding intruder in the cockpit is not a plausible scenario.
However passengers are not laughing. They worry about the possibility.
"Absolutely. Then we'd all be in trouble," said Regina Danko.
Congressman Pat Meehan, who serves on the Homeland Security committee, says the airlines should at least reconsider the courtesy of allowing pilots from other airlines to ride in the cockpit.
"I think what we're going to be asking for is a revisiting of the credentialing and other kinds of things that would allow that process to work," said Rep. Meehan.
Meanwhile, Jeannard is being held on a $1 million bail. The US Attorney is also considering filing more serious federal charges.