North American Aviation X-15 air drop from Boeing NB-52A Stratofortress 52-003 – Copy Published on November 10, 2012 in 9 November 1961Full resolution (862 × 528) ← Previous Next → The Number Two North American Aviation X-15, 56-6671, is dropped from the Boeing NB-52A Stratofortress, 52-003. (NASA)