"Think of this as the ultimate 'divorce your old airline' deal," Frontier CEO Barry Biffle said in the release—which, by the way, didn't mention Southwest by name. "If travelers show us the love, we'll make these perks permanent."

A low-cost airline that recently paid a $2.2 million penalty for attempting to deceive its customers during the pandemic has joined a chorus of critique against Southwest Airlines over its recent bag policy shift.

Frontier announced the limited time offer a week after rival Southwest Airlines ended its "bags fly free" policy for most travelers.