You\u2019ve been on enough business trips to know what awaits you at the airport: interminable delays, canceled flights and frazzled travelers trapped for hours in waiting areas. The annual passenger volume of 733 million in 2000 is expected to jump to 1.2 billion by 2002, according to Federal Aviation Administration predictions. Does it have to be this way? One MIT professor says no.In his recent report "Free-Flight and En Route Air Safety: A First-Order Analysis," Arnold Barnett of MIT\u2019s Sloan School of Management proposes a complete reshuffling of the nation\u2019s air traffic patterns. Currently, planes do not fly from point A to point B in a straight line. They follow predetermined routes, much like an interstate highway system in the sky. Free-flight routes would take a more direct path from takeoff to landing. "Recent advances in technology raise the possibility that present arrangements can be replaced by a free-flight regime, under which planes could travel directly from one city to another," Barnett states in his report. Such technological advances include GPS for airplane tracking and routing, air traffic control automation that makes it easier for controllers to manage increased traffic, and enhanced collision avoidance systems.Barnett contends that airlines can shave a few minutes off most flights and save an average of 2 percent in fuel consumption if they follow his plan, saving as much as $1 billion per year, collectively, for domestic airlines. The free-flight patterns would also allow for a greater number of flights, which would ease airport congestion.