The thread on first ever BA flight got me thinking on what has been the most unusual aircraft I flew on a BA operated flight - I could say the Concorde but that was on the timetable for many years.
For me it was a Gulfstream 1 btw MAN-ABZ in the spring of 1987 - a two engine prop.
I think the airline that owned the aircraft was Peregrine Air Services Ltd.

Any other good examples.