Every night between 11:30 p.m. and 2:30 a.m., nearly windowless jets with distinctive brown tails converge on Louisville, KY. One by one, about 90 aircraft in the United Parcel Service fleet land at the company's distribution hub flanking the Louisville airport, disgorge some 600,000 parcels, reload and hit the sky again. The system is remarkably efficient, and it has helped to keep UPS aloft as the nation's ninth largest airline.

But with the parcel delivery business expanding and the midnight skies over Louisville growing crowded, UPS is turning to new technology to compress arrivals and departures. In a radical experiment that may provide a glimpse into the future of air traffic control, UPS is embracing new satellite-based systems, hoping to wean itself off conventional radar-based technologies. Using the new digital tools, pilots would glance at cockpit displays showing their precise position, the positions of other UPS planes and a map of the airport and its runways-a display enabled by a combination of satellite positioning technology and digital datalinks between aircraft. Air traffic controllers would still run the show, but pilots would gain a tool to maintain more precise spacing on takeoff and landing.

If the UPS experiment works, says Dave Ford, a top Federal Aviation Administration official involved with the cargo airline's initiative, it could provide a model for enhancing safety and efficiency in the nation's overall air traffic control system. "One goal is to reduce runway incursions and accidents. We think this technology could help us in those areas. And we think there is a big link to efficiency," he says.

Efficiency is definitely the spur for UPS. "We believe we can increase our throughput with the same airport infrastructure," says company spokesman Ken Shapero. "If we can bring planes in faster or out faster, we can beat our competition." UPS predicts the technology will yield a 20 percent capacity jump at Louisville. A reduction of 20 to 30 seconds between some landings and takeoffs could shave about a half hour from the company's nightly sorting operation, a significant savings when your business hinges on delivering parcels on time. The numbers are so compelling that UPS is preparing to seek FAA approval later this year to use the system for approach and departure spacing at Louisville and is banding with other cargo carriers to push for even broader implementation.