One year after the deadly airline crash of Continental 3407 in Buffalo, NY, FRONTLINE investigates the accident 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 been a huge boon to consumers, and the industry insists that the skies remain safe. But many insiders are worried that now, 30 years after airline deregulation, the aviation system is being stretched beyond its capacity to deliver service that is both cheap and safe.