A union representing American Airlines Group Inc. pilots said Monday its members had approved a strike mandate ahead of the busy summer travel season, although the chances of an actual labor disruption remain slim.

The Allied Pilots Association (APA), which represents 15,000 American Airlines pilots, held a strike authorization vote in April to put pressure on the Texas-based carrier for higher salary and better working conditions, even as the two sides closed in on an agreement in principle.

More than 96% of the APA membership participated in the vote and over 99% voted in favor of authorizing a strike, the union said in a statement.

"We remain confident that an agreement for our pilots is within reach and can be finalized quickly. The finish line is in sight," American Airlines said in a statement.

The airline's pilots received their last pay increase in 2019.

Despite the vote, it would be hard for pilots to walk off their jobs because of a complex labor process in the United States that makes it difficult for airline workers to strike.

In March, Delta Air Lines pilots ratified a new contract that includes $7 billion in cumulative increases in pay and benefits over four years.

American's chief executive has said the carrier is prepared to match the pay rates and profit-sharing formula that rival Delta provided in its new contract.

Some airline executives are concerned that hefty pilot pay raises will inflate fixed costs and make it tougher to repair debt-laden balance sheets.

APA on Monday said its members will conduct informational picketing from 11 a.m. to 1 p.m. local time at all ten of the airline's major hubs including Boston (BOS) and Los Angeles (LAX).