From the cockpit of his United Airlines DC-8, en route from Chicago to Seattle at 37,000 feet, Capt. Homer Peterson first saw a broad vapor trail, much wider than that of a plane, just above the western horizon. Then he saw that the vapor was led by a glowing reddish-white object, followed by a flaming tail. Suddenly the object exploded like buckshot, each piece trailing fire. Spectacular though the explosion was, it did not take Capt. Peterson by surprise. About three hours before, he had received a TIP (Tracking and Impact Prediction) from the North American Air Defense Command, through his airline's operations office. The TIP had warned him to be on the lookout for a man-made object that nized reporting was done by United; then the field was opened up. Today 68 airlines make up the net, 50 of them outside the U.S. Only five major airlines in the world do not belong to the chain, one of which is Russia's Aeroflot, which wrote last year that it was waiting for the Soviet Academy of Sciences to decide whether such a project is as valuable as it is cracked up to be. The other holdouts are Trans World Airlines, Japan Air Lines, Scandinavian Air Service and Air France. Still under Roth's direction, VFON now represents almost 30,000 flight crew members who fly almost two million miles of air routes, most of them unduplicated. There have been 41 reports submitted on 14 reentering space objects (at least half of them Russian), wire and all radio reception-but, strangely, not transmission-cut out. The pilot who reported the sighting has been guaranteed anonymity by both VFON and Dr. Condon-a necessity if the network is going to receive any UFO reports at all. It's a matter of regaining the pilots' trust, Roth says. Besides the Smithsonian Astrophysical Observatory and the University of Colorado, VFON sends data of various kinds to the Environmental Science Services Administration, Northwestern University, the University of Arizona and a saucer-spotting organization called the National Investigations Committee for Aerial Phenomena. Even the National Aeronautics and Space Administration is interested; last month Roth briefed a space agency team