Not happened to me, but one of my friends was on the flight.
Indian Airlines, Madras - Bangkok, one hour into the the three hour flight, pilot informs plane returning back due to tech, landed back in Madras , pax waited for a couple of hours, switched to another aircraft.
90 minutes on, beleive it or not, the new aircraft develops tech problems, plane return backs to Chennai again.
Another 6 hours later, third time lucky- the latest aircraft made it through!!! (All three a/c were A320s).