Flight attendants associated with American Airlines overwhelmingly approved a strike authorization vote and are threatening to go on strike if their demands are not met for more pay and other benefits, according to union representatives.

In addition to wage increases of up to 20.5 percent, flight attendants will now be paid for boarding. The pay bumps comes after a long negotiation process.

Frontier Airlines flight attendants voted to authorize a strike over a business model change they say has resulted in less pay, the Association of Flight Attendants announced Wednesday. The vote was spurred by the Denver-based airline switching to a business model that includes more one-day trips and fewer multi-day trips for flight attendants,