Federal Aviation Administrator Randy Babbitt expressed reluctance Thursday to increase the number of flight hours required to be an airline co-pilot, a key safety recommendation arising from an airline crash in upstate New York last February.

Members of Congress and families of the 50 people killed in the crash of Continental Express Flight 3407 near Buffalo have urged the FAA to require that all airline pilots have a minimum of 1,500 hours of flying experience.

Only captains are now required to have that many hours of experience; first officers can have as few as 250 hours.

Babbitt told a Senate panel he thinks it's more important to address gaps in the type of training required of all pilots than to select a set number of hours in the cockpit as the threshold for piloting an airliner.

"Raising the quantity of hours without raising the quality and nature of the time ... may not ensure the improved proficiency we all want," Babbitt said at a hearing of the Senate Commerce, Science and Transportation Committee's aviation subcommittee.

Babbitt also acknowledged the agency's schedule for proposing a new regulation dealing with pilot fatigue has slipped. He had previously said he hoped to publicly propose a new fatigue rule by the end of this year. He said Thursday he now expects to propose the rule by this spring, and make it final by the end of 2010.

The National Transportation Safety Board has been urging FAA for 19 years to update regulations related to pilot fatigue.

FAA is also currently working on new regulations to address pilot training and experience.

Many captains and first officers at major airlines have far more than 1,500 hours flight experience. However, major airlines now farm out much of the short haul flying between cities only a few hundred miles apart to smaller, regional airlines. Those airlines can offer cheaper fares in part by hiring less experienced pilots and paying them lower salaries.

Flight 3407 was operated for Continental Airlines by Colgan Air Inc. of Manassas, Va. The flight's first officer, Rebecca Shaw, had a salary of about $16,000 in 2008 and lived with her parents near Seattle. She spent all night commuting across the country in order to reach Newark Liberty International Airport in New Jersey so that she could make the flight to Buffalo.

A cockpit voice recorder transcript indicates she was feeling ill, but was reluctant to tell Colgan she wasn't well enough to make the flight to Buffalo because she'd have to pay for a hotel room.