The Federal Aviation Administration measure, which was fought for years by airlines over cost and scheduling concerns, aims to keep flight crews as fresh and alert as possible and reduce mistakes.

"This new rule gives pilots enough time to get the rest they really need," said Transportation Secretary Ray LaHood.

The policy, which was last updated in the mid-1980s, would reduce the maximum work day from 16 hours to 14 hours per day. Pilots would get at least 30 hours free from duty on a weekly basis, a 25 percent increase over current policy.

The rule would cost airlines $297 million over 10 years. Cargo carriers are exempt.

The change was ordered by Congress following the crash of a commuter plane in Buffalo, New York, in 2009 that killed 50 people. While investigators did not blame the crash on fatigue, they did say the crew was probably overtired during the late night flight.

Airlines have two years to comply. (Reporting by John Crawley in Washington)

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