From Wikipedia's article on the Lubbock Lights:
"The three professors became determined to view the objects again and perhaps discover their identity. On September 5, 1951, all three men, along with two other professors from Texas Tech, were sitting in Dr. Robinson's frontyard when the lights flew overhead. According to Dr. Grayson Mead the lights "appeared to be about the size of a dinner plate and they were greenish-blue, slightly fluorescent in color. They were smaller than the full moon at the horizon. There were about a dozen to fifteen of these lights... they were absolutely circular... it gave all of us... an extremely eerie feeling." Mead claimed that the lights could not have been birds, but he also stated that they "went over so fast... that we wished we could have had a better look." The professors observed one formation of lights flying above a thin cloud at about 2,000 feet (610 m); this allowed them to calculate that the lights were traveling at over 600 miles per hour (970 km/h) "
In the '40s discs were reported flying in similar formations.