The Teamsters group representing pilots at Republic Airways is balking at allowing a vote on the company's contract offer, deepening the rift between labor and management at the regional airline.
The Indianapolis company's shares plunged 37 percent on Wednesday.
Republic has threatened to begin a restructuring process if pilots don't approve the proposal it offered last week, which it termed its last and best offer.
Jim Clark, the president of Teamsters Local 357, said that the Teamsters national organization could override the local and order a ratification vote. Clark said he favors resuming negotiations with Republic.
Republic did not immediately respond for comment. Republic operates regional flights for bigger airlines including American, Delta and United.
Shares of Republic Airways Holdings Inc. fell $1.23 to close at $2.12.