WASHINGTON -- The Northwest Airlines pilots who overshot a U.S. airport by 150 miles are appealing their license revocations with the National Transportation Safety Board.

The appeals were filed late Wednesday, said board spokesman Ted Lopatkiewicz. He said appeals typically are heard by an administrative law judge with the board within 120 days.

The Federal Aviation Administration revoked the licenses of Capt. Timothy Cheney and First Officer Richard Cole last week. The agency said the pilots put the 144 passengers of Northwest Flight 188 in serious danger on Oct. 21 when they failed to communicate with anyone on the ground for 91 minutes despite repeated attempts by air traffic controllers and their own airline to reach them.

There is a discrepancy between FAA and NTSB over how long the flight was without radio contact. FAA said 91 minutes in letters sent to the pilots six days after the incident. NTSB officials told reporters Thursday it was 77 minutes. FAA spokeswoman Laura Brown would not confirm either figure, saying the agency is working on a timeline of the event and will know more next week.

Cheney and Cole told investigators they lost track of time and place while working on crew scheduling on their laptops. They said they did not realize their situation until a flight attendant contacted them on the intercom to ask when the plane would be landing. By then, the Airbus A320 was over Wisconsin, north of the airport at Minneapolis, Minnesota, and flying at 37,000 feet (11,280 meters). The pilots turned the plane around and landed safely in Minneapolis.

Attorneys for the pilots would not comment Thursday.

The incident raised national security concerns. Senior White House officials were notified by the White House situation room during the incident. Fighter jets in two locations were moments away from taking off to track down the errant airliner when contact was re-established.

FAA and NTSB investigators were in Colorado on Wednesday, where they interviewed controllers at the FAA's radar center near Denver. FAA investigators also spoke with military officials at the North American Aerospace Defense Command in Colorado Springs, south of the state capital.

Investigators plan to interview controllers in Minneapolis on Friday, NTSB spokesman Keith Holloway said.

The U.S. military would have launched fighters if officials had been notified sooner. Air Force Gen. Gene Renuart, who heads U.S. Northern Command, has said he learned of the incident just four or five minutes before the FAA regained contact with the pilots. The delay has raised questions about whether controllers complied with procedures put in place after the Sept. 11, 2001, terror attacks against the United States.

Two bills were introduced in the Senate Thursday to ban nonessential electronics, including personal laptops, from the cockpit.

"We simply want to ensure that, with all of the electronic distractions available these days, flying the plane remains the one and only focus," Democratic Sen. Robert Menendez, author of one of the bills, said in a statement.

FAA Administrator Randy Babbitt said Wednesday the Northwest incident resulted from an erosion of professionalism among commercial airline pilots.

"I think that this is a sign of a much bigger problem," Babbitt said in a speech to an aviation club. "I can't regulate professionalism. With everything we know about human factors, there are still those who just ignore the commonsense rules of safety."