SkyWest Inc., which operates regional flights for carriers including United Airlines, said its pilots rejected an organizing effort by the Air Line Pilots Association.

Flight crews at the St. George-based airline opted "to remain union-free" in balloting that ended Tuesday, SkyWest spokeswoman Marissa Snow said in a telephone interview.

The vote marked the third rebuff of an outside union by SkyWest pilots, who have "in-house" representation, Snow said. In September, ALPA-represented pilots at SkyWest's Atlantic Southeast Airlines unit reached a tentative contract with that carrier, which SkyWest bought from Delta Air Lines Inc. in 2005.

The ASA accord "exceeds SkyWest in pay, etc., which is another reason I'm surprised" that Tuesday's vote failed, union spokesman Pete Janhunen said.

SkyWest has 2,781 pilots. Of 911 pilots who voted, 904 favored organizing, Janhunen said. The union would have needed 395 more pilots to participate in the election to meet required thresholds, he said. "It was a turnout problem."