Flight attendants at Allegiant Air want to vote on joining the Transport Workers Union of America.
The union said on Thursday that Allegiant flight attendants filed a petition with the National Mediation Board, which governs airline unions. The union says the board is supposed to set an election date within 45 days.
The same union represents flight attendants at Southwest Airlines Co.
Allegiant is a small, discount airline based in Las Vegas that mostly carries vacationers to leisure destinations. It has 420 flight attendants.
Allegiant is nonunion. Parent company Allegiant Travel Co. listed "unionization efforts" as one of the risks to its business when it reported a quarterly profit of $13.2 million on Wednesday.