Night Siege: The Hudson Valley UFO Sightings

Night Siege (Ballantine, 1987) documents the wave of sightings in New York's Hudson Valley and western Connecticut from 1982 to 1986, when thousands of people reported a huge, silent, boomerang-shaped array of lights moving slowly over highways and towns. J. Allen Hynek began the investigation with Philip Imbrogno, and the book was completed with the journalist Bob Pratt after Hynek's death in 1986.

The authors argue the object was a single structured craft that a formation of aircraft could not explain. The best-known counter-explanation is that a group of pilots from Stormville, New York, flew light aircraft in tight formation at night with their lights on as a stunt; some witnesses saw planes break formation. Both readings remain in the literature.

Sources: Wikipedia