An American Airlines Airbus A321 plane takes off from Los Angeles International airport
An American Airlines Airbus A321-200 plane takes off from Los Angeles International airport (LAX) in Los Angeles, California, U.S. March 28, 2018. Reuters

The union representing American Airlines pilots will take a strike authorization vote in April, underscoring a broader push by North American pilots to make gains on salary and working conditions as air traffic increases sharply.

The vote announced by the union on Thursday will conclude on April 30 and follows Delta Air Lines pilots ratifying a new contract earlier this month that includes $7 billion in cumulative increases in pay and benefits over four years.

The deal is widely seen to be a benchmark for contract negotiations at rival U.S. carriers.

"Management must understand that they need to demonstrate the same level of commitment to bargaining that other airline management teams have shown in recent months," the Allied Pilots Association said in a bulletin to members.

In an emailed statement on Thursday, the Texas-based carrier said it looks "forward to reaching an agreement with APA quickly so that American's pilots can benefit from meaningful enhancements to their pay and quality of life."

Even if the union gets a mandate, it would be very hard for pilots to walk off the job because of a complex labor process in the United States that makes it difficult for airline workers to strike.

The union, which represents more than 14,500 pilots at American Airlines, said it is "cautiously optimistic of management's commitments and presence at the table," but called the next few weeks critical.

Earlier this week American's chief executive 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.