Under pressure, airlines begin mandating passenger face masks

Delta Air Lines, American Airlines and United Airlines on Thursday mandated that passengers must wear face masks on board planes, and more are likely to follow, following intense pressure from airline unions and some lawmakers.

Flight attendant unions and Democratic lawmakers have been pressing the federal government to mandate masks on planes. Regulators have so far resisted the pressure, but the airline industry is beginning to turn toward implementing mask requirements piecemeal anyway.

Delta and American's news followed similar announcements by JetBlue Airways and Frontier Airlines. Other carriers are likely to follow suit - so far, Dallas-based Southwest Airlines is the lone holdout among the nation's biggest airlines.