B Fraser, the story probably stems from the
Skyshield exercises of the early 1960s.
I doubt whether the Vulcan would have mixed with civilian traffic as all civilian flying was grounded for the exercises. Perhaps someone was thinking of the 27 Sqn aircraft which landed at Plattsburgh AFB, New York, after giving NORAD's defending F-102s the slip?
See
http://www.pprune.org/1303092-post422.html
