The Association of Professional Flight Attendants formally requested to be "released" from federal mediation talks with American Airlines.
APFA president Laura Glading said she met with the National Mediation Board at 1 p.m. EDT and submitted a letter requesting the release, which is the first step towards a possible strike.
"The hope is once the company feels the pressure, we'll get a deal," Glading said. "But we're not afraid to go on strike if we have to."
The flight attendants union is the second American work group that has asked for "release" in the past week. On Thursday, the Transport Workers Union, which represents baggage handlers, mechanics and dispatchers, made a similar request of the NMB.
The Fort Worth-based carrier said it remains committed to the negotiation process with the APFA.
"American Airlines continues to believe that talk of 'impasse' or 'release' at this time is premature, unproductive and can be detrimental to the process, undermining the ability of both parties to get a deal that helps American and all of its employees achieve long-term success," said American spokeswoman Missy Latham.
Under the Railway Labor Act, unions cannot strike without first asking the National Mediation Board to declare an impasse to seek release from negotiations. If the federal board decides to release the union from mediation, a 30-day cooling off period must expire before a strike or a lockout.