Hmm; perhaps I should relate my most recent UAP experience. As I've noted before, I've seen several different types of UFO, and most of them are related somewhere on this site; but I have generally found a convincing explanation for each of them. (Convincing to me, anyhow).
So: the most recent event happened about 2 weeks ago. We often have helicopters flying over York, sightseeing around the Minster and so on; this area is outside most commercial air lanes, so the only planes we see are tourist craft, light aircraft and military craft. I went outside, and there was a helicopter buzzing around - presumably one of the tourist trips. Looking up I could see something- it looked like a very old helicopter, perhaps a Sigorsky, with the weird bubble shaped cockpit at the front.
But it didn't look right at all. The wheels were somehow invisible, and there was absolutely no sign of the rotor blades above the copter. And weirdly, the bubble-shaped cockpit was constantly facing directly towards me, so that it looked like a light-bulb floating in the sky. But I could hear the rotors, so I knew this must have been an illusion.
Then the actual helicopter came into view - a lot lower down, and a lot farther away. Whatever I had been looking at, it wasn't a helicopter.
Gradually, I realised that the thing I had been looking at was probably some kind of large grey balloon - actually, I had no idea exactly how large, except it looked similar in size to the real helicopter. My mysterious balloon drifted across the sky towards the west (an unusual wind direction, but I later confirmed that the wind was blowing from the east, so the object was indeed flying with the wind).
Eventually it disappeared into the clouds - a fairly low layer of stratus, 2000-3000 feet perhaps, high enough to allow the real helicopter to get a good view of the Minster.
So, I'm completely flummoxed; why should anyone set off (largish) balloons in the middle of the day, posing a potential hazard to commercial tourist flights. Was it even a balloon? Who knows?