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, union leaders said in a news release. “Frontier flight attendants are struggling to earn a living because of management’s new ‘out-and-back’ model.