(Las Vegas, NV) –  The union representing 600 flight attendants at Las Vegas-based Allegiant Air says contract talks are stalled and it is asking the National Mediation Board to step in.

Transport Workers Union of America negotiator and flight attendant Debra Petersen-Barber said in a statement Friday that tentative agreements have been reached on several difficult work issues.

But she says the two sides haven’t agreed on issues including pay, compensation for extended delays and union dues deductions.

Allegiant pilots last month voted to be represented by the International Brotherhood of Teamsters.

Publicly traded Allegiant Travel Co. specializes in airline service between smaller cities and resort destinations.