By Jeffrey Dastin

NEW YORK, Jan 4 (Reuters) - The union representing American Airlines pilots approved the carrier's final contract offer late Saturday, paving the way for a retroactive 23 percent wage hike if its members concur in a vote this month.

The news was a step toward concluding contracts to represent all workers at the airline, which became the world's largest by passenger traffic after it merged with US Airways in Dec. 2013. Its flight attendants received a new contract in arbitration last month, and while deals for other work groups such as ticketing agents are pending, the carrier is poised to avoid the multi-year contract delays that have plagued other merged airlines.

"We are pleased our pilots will have a chance to vote on a contract that provides an immediate 23 percent pay increase and recognizes their contributions at American," company spokesman Casey Norton said in an emailed statement.

Yet the board of the Allied Pilots Association (APA), which represents American's pilots, said in a Saturday release that it was "disappointed with this latest turn of events," despite agreeing to the contract.

It called some of the contract's language incomplete, with regard to combining how pilots bid for domestic and international flights. The union said it will work with management this week to finalize this language before sending the agreement to rank and file pilots to review.

A pilot-wide vote is expected to occur this month, but APA has yet to set the date.

APA also expressed frustration that earlier on Saturday management rejected a proposal to give pilots pay for each calendar day they spend away from home, even if they're in a hotel waiting for an assignment, a work rule in place at competitors Delta Air Lines and United Airlines, a union spokesman said.

The company said last month that the contract on the table was its final offer.

If American's pilots reject the contract, just like its flight attendants rejected the deal their union had negotiated, the process will move to binding arbitration in February, which would result in wage increases smaller than what the company had offered.

The company had set Jan. 3 as an early deadline for APA, saying pilots would not receive raises retroactive to Dec. 2 had APA's board not approved the contract in time.

(Reporting By Jeffrey Dastin; Editing by Meredith Mazzilli)