Weird stuff can happen. Most NY to Boston traffic was the Eastern Shuttle out of LaGuardia, but there was a late afternoon (5pm?) on American, that closed a loop placing a DC-10 at Logan for a busy route the next morning. On arrival at JFK, the DC-10 was taken o/o/s for a maintenance issue. Needing a widebody for early AM in Boston, they swapped in a 747. A normally empty plane now looked like a scene from a ghost flight movie...Nothing as profound as that since, an A320/319 swap on UA, and a 767 to 757 swap on TWA when the 67 had to return to LAX because of unresolvable maintenance issues. The 57 was new to TW they had just put them into service. But in those cases, the same folks can fly them as the original planes.