SkyWest Airlines cites new regulations for ending service from Modesto City-County Airport (KMOD), Modesto, California

A regional airline is ending service at Modesto City-County Airport, blaming new pilot rest rules for increasing the cost of operating from the largest city in Stanislaus County.

SkyWest Airlines said it will stop serving Modesto on Wednesday, leaving the airport without regular airline service for the first time in decades.

Among other reasons cited by the airline for pulling out is a new federal regulation that requires airlines to give pilots more rest time between shifts. The regulations took effect in January.

The federal requirement increased the cost of serving the regional airport, and the demand for air service from Modesto does not justify the extra cost, SkyWest spokesman Wes Horrocks said.

"This was a difficult decision to make and we will continue to evaluate opportunities to return to Modesto in the future," the airline said in a statement.

The airline industry had several years to prepare for the new regulations, which entitle pilots to at least 10 hours of rest between shifts, up from eight hours under the old rules.

The sweeping changes came partly in response to the February 2009 crash of Colgan Air Flight 3407. The plane stalled and crashed over western New York, killing 50 people. Pilot error was determined to be the cause of the crash but investigators also cited pilot fatigue as contributing to the accident.

When the federal rule was under consideration, airlines said they would be forced to hire more pilots to meet the continuing demand for air travel and to comply with the latest regulations.