[13thLetter]

> The main difference is that all of those phenomenon were unidentified: the pilots never had sufficient detail to match their evidence to a real-world experience.

There were no real-world experiences of UFOs, but it's not correct to say that pilots didn't know what to expect -- flying saucers with a very specific description were a well-established part of popular culture. A saucer-shaped object at a great distance that moved quickly, made sharp turns which would be impossible for a fixed-wing aircraft, and which would eventually disappear as if it had moved straight away at high speed, was the standard description. It would have been in the mind of any pilot, and indeed exactly that description popped up innumerable times in the UFO reports.