Capt. Willis T. Sperry and the American Airlines DC-6 sighting near Mount Vernon, Virginia

Capt. Willis T. Sperry started flying at age 11 and joined American Airlines by 1939. Ruppelt credited him with more than 15,000 flying hours. On May 29, 1950, he commanded DC-6 Flight 49 from Washington to Nashville. First Officer William "Bill" Gates and Flight Engineer Robert Arnholt completed the cockpit crew.

After leaving Washington National Airport, the airliner headed 240 degrees and climbed through 7,500 feet. One account put the time at 9:20 p.m.; Sperry later said 9:30. The moon was about 30 degrees above the horizon. Seven miles west of Mount Vernon, Gates saw a rapidly growing light and shouted, "Watch it, watch it!" Sperry called it "a brilliant, diffused, bluish light of fluorescent type" coming "from out of the west" at their altitude.

Sperry banked 45 degrees to the right. The light swept down their left side, from 11 o'clock to 7 o'clock, then "seemed to stop, possibly five seconds, and changed its course to parallel us on our left." It passed between the crew and the moon, briefly revealing its outline. "The shape of a torpedo or submarine," Sperry wrote, "except that there were no protruding fins or external structure of any kind." Its length was about half the moon's diameter.

Then it circled behind the airliner. "It's over here," the copilot said, and both men watched it off the right side. Finally it reversed and moved east, climbing gradually, shrinking to "about the magnitude of a very bright star" before it disappeared. The whole encounter lasted "approximately only one minute."

Washington radar had detected nothing. In 1950 Sperry wrote that one passenger saw "an extremely bright light." A 1955 interview recorded two or three passengers and the stewardess. By 1964 Sperry put the number at 12. That same evening another American Airlines captain, Hank Myers, flying between Nashville and Knoxville, reported "a brilliant bluish object."

On May 30 a major at the Pentagon telephoned Sperry long distance in Tulsa. Newspapers carried the story on May 30 and 31. Sperry's letter appeared in Flying magazine in September, and Donald Keyhoe wrote about the case in True.

February 4, 1955. W. B. Klemperer interviewed Sperry for Project Blue Book. Ruppelt, who had led Blue Book from 1951 to 1953, retold the case in his 1956 book. In his version the crew saw "the dark silhouette of a 'wingless B-29'" with "a blue flame shooting out the tail end." He recorded no official finding. James E. McDonald later interviewed Sperry as well, and researcher Brad Sparks lists the case as Case 376 in his catalogue of Blue Book Unknowns.

March 17, 2000. Sperry, then 98, sat down with Thomas Tulien and Brad Sparks of the Sign Oral History Project. He died a few months later.

The Air Force was not impressed. One general reportedly called it "all a bunch of damned nonsense" and said the pilots were "just fatigued." Myers described his own light as a "shooting star" that moved horizontally. Yet no published explanation has ever been offered for a light that stopped, paced an airliner and showed a hull against the moon. In 1964 Sperry said, "from that time until now I have never been able to decide just what it was that we saw."

In 1956 he played himself in Unidentified Flying Objects: The True Story of Flying Saucers, alongside Nicholas Mariana and Delbert Newhouse. It became a lasting image of a seasoned airline captain facing the unexplained.