(CNN) -- The man who conned his way into the cockpit of an US Airways flight in March pleaded guilty Wednesday in Philadelphia to one count of fraud in connection with an identification document.
Philippe Jeannard, 61, had used his mother's old Air France employee documents in an attempt to pass as a pilot and score a free ride in the jump seat of a plane after he had been denied an upgrade to business class, according to the original complaint.
Jeannard was wearing a white, button-down shirt with an Air France logo over the pocket and a black jacket with four gold stripes on the epaulets, similar to one worn by pilots, the complaint said. He identified himself to the gate supervisor at Philadelphia International Airport as an Air France pilot.
He entered the cockpit, where two pilots were performing preflight duties and told pilots he was an Air France Boeing 747 pilot.
U.S. District Court Judge Gene E.K. Pratter has not yet scheduled a sentencing hearing. Jeannard faces an advisory sentencing guideline of up to six months in prison plus deportation proceedings.
The case was investigated by the Immigration and Customs Enforcement Homeland Security Investigations, the FBI and the Philadelphia Police Department.
"He identified himself as a pilot and started to sit in the jump seat," Philadelphia Inspector Joseph Sullivan told CNN in March. "But he immediately had a problem getting strapped in, and it was obvious to the real pilots that he couldn't be a pilot. He didn't know what he was doing."
The gate agent told Jeannard he would have to fill out paperwork to use the jump seat, but the man didn't have credentials, police said.
The captain then told him to leave the cockpit area, and Jeannard became irate. Brian L. Jones, a special agent with Homeland Security Investigations, described him in an affidavit as difficult and verbally abusive to a flight attendant and gate supervisor.
Jeannard was taken off the aircraft. The flight departed, and a US Airways agent tried to book him on another flight to West Palm Beach, Florida, his final destination.
According to the criminal complaint, after returning to the gate, Jeannard covered his Air France shirt with a sweater and acknowledged to a US Airways manager that he was not an Air France employee.
Jeannard was taken to the Philadelphia Police Department's airport holding cell and arrested on charges of trespassing, tampering with records, false impersonating and false identification to law enforcement authorities.
Police discovered documents appearing to be Air France checklists and flight plans in Jeannard's briefcase, according to Jones' complaint.
It said Jeannard admitted to having falsified his mother's Air France identification card, which the airline said was real. Jones said Jeannard had replaced his mother's information with his own name and photograph; it identified him as an Airbus A380 crew member. Air France spokesman Cedric Leurquin described it as a bad fake of an Air France crew badge.
Jeannard, who is from La Rochelle, France, is a retired winemaker who was changing planes on his way from France to Florida, police inspector Sullivan said.
Jeannard at one point remarked that he "hated Americans," police said, but investigators have not found any link to terrorism, a federal law enforcement official said.
Attempts to reach Jeannard's lawyer were not immediately successful.
CNN's Susan Candiotti contributed to this report.