(Reuters) -Frontier Airlines pilots have voted to authorize a strike, the Air Line Pilots Association said on Tuesday.

99% of the votes cast were in favor of the strike, the ALPA added. According to its website, the ALPA covers 2,200 pilots at the carrier.

While the strike authorization does not guarantee a work stoppage, it is a vital tool in negotiations.

Frontier pilots' contracts became amendable in January and have been engaged in mediated talks under the Railway Labor Act since then.

"Negotiations for a new collective bargaining agreement have yet to yield a market-based contract that aligns with industry standards," the ALPA said.

The announcement comes at a time when unions across the U.S. are pushing for better pay and work conditions.