Unidentified jet aircraft — extraordinary acceleration, off Dutch coast

A November 4, 1948 USAFE intelligence cable (Confidential) reports that three crews of the 307th Bomb Group, during Operation Daggar, observed an unidentified aircraft on September 25, 1948 off the west coast of Holland at grid 5155N/0355E. The object was initially cruising at normal jet speed on heading 120 degrees, then suddenly left smoke trails and condensation trails accompanied by sudden acceleration and a climb, described as employing probably rocket assists with 'tremendous reserve power, more than normal cruising speed for jets of the 1947 variety.' The object never came within identification range. USAFE assessed this B-2 (probably true, not confirmed).

“A/C began leaving smoke trails and condensation trails accompanied by sudden acceleration and then climb. Generally agreed by observers that it was a single jet propelled A/C employing probably rocket assists with tremendous reserve power, more than normal cruising speed for jets of the 1947 variety. Never within identification range; its course did not indicate its purpose.”

Precise coordinates given (51°55'N, 3°55'E). Three independent crews corroborated. USAFE evaluation B-2. Document classified TOP SECRET at file level, individual item CONFIDENTIAL. OCR is relatively clean for this passage.