David McCallum and Lawrence Montaigne played fellow P.O.W.s in The Great Escape (1963).
The abort destruction of the missile uses the same stock footage seen at the climax of the The Man from U.N.C.L.E.'s "The Love Affair".
The missile first shown in the back of a van and then several times thereafter, appears to be an AIM-7 Sparrow. This radar-guided air-to-air missile was one of the standard weapons carried on US fighter aircraft at that time. The blue color seen on the fins of the missile indicates that it's an inert training round.