– Unionized pilots at Spirit Airlines are gearing up for a key vote starting Aug. 21 that could pave the way for them to strike if contract negotiations with the low-cost carrier hit an impasse.

Leaders of Spirit's pilot group announced Monday they agreed unanimously to put a strike-authorization ballot before 1,600 unionized pilots for voting through Sept. 8.

If the measure passes, the pilots could only call for a strike if released from supervised talks by the National Mediation Board and following a 30-day cooling off-period.

Spirit and its pilots, represented by the Air Line Pilot Association International, have been in contract negotiations for more than two and a half years.

"Spirit pilots are not looking to strike. We are looking for an industry-standard contract that brings our compensation in line with our fellow pilots — that remains our main goal," said Capt. Stuart Morrison, chairman of the Spirit ALPA, in a statement. "However, we are willing to take any lawful steps necessary, including a legal strike, to achieve the contract every Spirit pilot has earned."

The union contends Spirit's pilots are compensated far less — as much as 40 percent — than their counterparts at other airlines flying similar routes and aircraft. They say their pay remains below industry standards even as the airline makes significant profits.

"I have no doubt that the result of this vote will send a clear message to our management that our pilot group is unified and ready to take every lawful action necessary to reach the contract we deserve," Morrison added. "It's time for our management to come to the table prepared to negotiate a market-rate contract."

A Spirit official could not be reached for comment on Monday.

During the second quarter, Spirit took a $45 million hit on its earnings due to an alleged work slowdown by the pilots that resulted in more than 850 flight cancellations. That included $25 million in lost revenue and $20 million in additional operating costs associated with rebooking passengers.