In a press conference with U.S. airline officials Thursday, several union leaders repeated the airlines' warning that U.S. workers will lose their jobs if domestic airlines are pushed out of key markets because of competition from three Gulf airlines.

They also repeated the allegations by U.S. airlines that Emirates [EMIRA.UL], Qatar Airways and Etihad Airways have received billions of dollars of subsidies from their home states, which those three carriers have strongly denied.

The Gulf carriers say U.S. airlines are losing market share because of their inferior service.

"This impacts our careers," said Rick Dominguez, the executive administrator of the Air Line Pilots Association. "We have an obligation to not only expose the (subsidies), but to call upon our government to make it right."

The allegations have created a politically charged dogfight, with companies such as FedEx Corp (>> FedEx Corporation) asking the Obama administration not to alter the "Open Skies" agreements, from which FedEx has benefited, and saying the U.S. airlines have protectionist interests.

Delta Air Lines (>> Delta Air Lines, Inc.), United Airlines (>> United Continental Holdings Inc) and American Airlines (>> American Airlines Group Inc) intend to release a 55 page white paper detailing the allegations against the Gulf carriers following demands from their opponents for a wider release.

(Reporting By Jeffrey Dastin in New York; Editing by Alan Crosby)