In this re-broadcast, FRONTLINE investigates the deadly crash of Continental 3407 outside Buffalo, NY, and discovers a dramatically changed airline industry, where regional carriers now account for half of the nation's daily departures. The rise of the regionals and arrival of low-cost carriers have kept prices low for consumers, and the industry insists the skies remain safe. But the Buffalo crash, and ensuing investigations like FRONTLINE's, reveal a host of serious safety concerns with today's aviation system - concerns that prompted the most sweeping airline safety law in more than a decade.