Richard Hall:
Air Force Lieutenant George H. Kinmon, Jr., a World War II combat veteran, was flying an F-51 out of Lawson AFB, Georgia, at 1340 hours when a white, disc-shaped UFO ("completely round and spinning in a clockwise direction") confronted his aircraft, at one point making a head-on pass at it.

Quotes from Air Force intelligence report:

"Object described as flat on top and bottom and appearing from a front view to have rounded edges and slightly beveled ... No vapor trails or exhaust or visible system of propulsion. Described as traveling at tremendous speed ... Pilot had leveled off at 8,500 feet altitude on a course of 247 degrees ... object dived from the sun in front and under the plane and continued to barrel-roll around the plane for a period of ten minutes, when it disappeared under the plane ... object was 300 to 400 feet from plane and appeared to be 10 to 15 feet in diameter ... Pilot states he felt disturbance in the air described as 'bump' when object passed under plane ... Pilot considered by associates to be highly reliable, of mature judgment and a creditable observer. Pilot notified tower, Robins AFB by radio and contacted fit svc [flight service] at Maxwell AFB ... Pilot unable to take photo due to camera malfunction."