Flew with a capt some years back who had an uncle on stratocruisers.I think they were
en route jfk gander when they witnessed one of those cigars with other attendant whatever.It was reported,photographed,not detected by any radar such as it was then,
witnessed by passengers etc. It flew in parallel with the stratocruiser until fighters were sent to investigate,wherupon the scout vehicles disappeared into the cigar and
it disappeared at high speed. What was more intersesting was the crew being met at gander by some form of security (us l think) ,had the flight log confiscated,and sworn to keep quiet about what they had seen.
Als had another friend on a CL44 cargo flight (tradewinds?) over the mediterranean
in the region of majorca at night having to take evasive action from something huge in the sky. Aircraft in front and behind also witnessed it ,including a US hecules
that stated that whatever it was looked like and appeared to be the size of a nuclear submarine!
This friend was not a crank and was as cynical as most people. Probably shrugged his shoulders and carried on reading the sun..This thing was not a ballon etc cos it manouevred at a great rate and moved awy at high speed.