Frontier Airlines expects a revenue boost from Spirit Airlines' collapse over the weekend, a shuttering that removed Spirit's capacity from the market overnight. "Drawing on the benefits realized from prior Spirit capacity adjustments, we believe their exit supports a [revenue per available seat mile] uplift of 3% to 5% going forward," Frontier's chief commercial officer, Bobby Schroeter, said on an earnings call Tuesday. Just before Spirit ceased operations , marking the biggest U.S. airline