The Federal Aviation Administration plans to outline a 10-year air traffic control modernization plan to squeeze 30 percent more traffic into the commercial aviation system while easing delays and increasing safety by giving pilots better information on weather problems and the location of other aircraft.

If the plan stays on schedule -- and there are plenty of skeptics inside and outside of FAA -- only three things will remain unchanged in the air traffic control system of next decade: controllers will give air traffic clearances and orders to pilots; pilots will fly planes; and planes can't fly through severe thunderstorms.

For the passenger, the plan, if executed properly, will mean better, faster, more frequent and safer service.

The need is great. After years of poorly executed FAA upgrade programs and a virtual ban on the building of new runways and airports because of community opposition, long delays and cancellations began rippling through the aviation system in the summer of 1999. The system is so saturated that one small problem can overwhelm the entire network. For example, a plane delayed five minutes on the runway at Newark International Airport now creates delays for more than 250 other planes as far away as Minneapolis, according to FAA documents. And individual planes are so full they cannot quickly accommodate spillover passengers from other flights that have been delayed or canceled.

Under a series of FAA-planned programs, the control of planes in the air and on the ground will gradually shift toward a satellite-based system. The FAA also plans to re-equip ground-based systems with digital radar and better software and controller displays. It also is counting on weather research that may someday give pilots and controllers up to six hours' notice to help them plan routes around bad weather even before it develops. The best meteorologists can do now is one hour.