DALLAS (Bloomberg) — Southwest Airlines Co. and leaders of its pilots union have agreed on tentative contract terms that would allow the largest low-fare carrier to bring the Boeing Co. 737-800 into its fleet.

The 5,800 members of the Southwest Airlines' Pilots Association will vote on the proposal from November 1 to December 1, the union said yesterday in a statement. If approved, the plan would set pay and work rules for flying the plane; extend the union's contract by a year, to August 2012; and add possible wage increases tied to the carrier's financial performance, the Dallas-based airline said.

Southwest said in August it was considering adding the larger 737-800 to all its fleet of 737 aircraft to carry more passengers on high-demand routes. The airline and its flight attendants last month reached a similar tentative agreement, which also must be voted on by members.

Southwest has said it will decide whether to add the 737- 800 by December 1. The airline agreed on September 26 to buy AirTran Holdings Inc. for $1.4 billion in cash and stock. The purchase would add the smaller Boeing 717 to Southwest's fleet.