FedEx Express pilots voted overwhelmingly to authorize a strike in a move they hope will help their union win a new contract that would include pay raises.

The Air Line Pilots Association said Wednesday that 99% of its FedEx members who took part voted to authorize a strike, and turnout was 97%.

Federal law prohibits airline unions from conducting strikes until U.S. mediators have declared negotiations at an impasse � which has not happened at FedEx � and even then, Congress and the president can block a walkout.

Unions, however, believe that the votes increase their leverage at the bargaining table. The pilots� union and Memphis, Tennessee-based FedEx have been negotiating for two years over a new contract while terms of the previous one remain in effect.

�Our goal is to reach an agreement, not to strike,� said Chris Norman, head of the union�s FedEx chapter.

FedEx said the pilots� vote will not affect company operations and that it is focused on reaching an agreement with pilots �that is fair to them, our other team members, and all other FedEx stakeholders.�

Pilots at Southwest Airlines and American Airlines recently voted to authorize strikes, and Delta Air Lines pilots did the same before reaching a contract that raised average pay 34% over four years.

(AP)