One of the cases was reported by Capt. F. E. C. Underhill, a veteran pilot with 30 years flying time, 18 of them with the Royal Air Force.  On Sept. 11, Capt. Underhill was piloting an Air Ferry Limited DC-6 west of Barcelona, Spain.  At 5:35 p.m., GMT, Underhill, his co-pilot and a steward sighted a metallic-looking cone-shaped object approaching the plane from the west.  Flying at a speed between 600 and 700 knots, the UFO crossed the aircraft's flight track, turned toward the plane, then sped away to the south.

"There was a definite solid object the like of which none of the crew...had ever seen before," Flight Officer Brian Dunlop stated.

Captain Underhill remarked that the UFO must have been under control...it definitely altered course substantially.

The case was investigated by London NICAP member Julian J. A. Hennessey.