Perfectly understandable for there to be life on other worlds, even intelligent life. It's a totally different thing to think that some other life has both solved the tyranny of interstellar distances AND decided to visit Earth (of all places!) AND kept it secret.
in 20,000 hours. I have seen green flash meteorites, shower of spark meteorites, Russian rocket stage re-entries, sun dogs, brokenspecrtres, sparks jumping inside the cockpit (in charged clouds near thunderstorms), large amature-launched balloons, St. Elmo's fire on the windows and lancing forward of the aircraft into clouds, satellite flares (the Starlink flares at the moment regularly confuse airline pilots on the radio who don't know what they are looking at), comets, planet alignments ... never anything I didn't understand or wasn't normally understandable with a small amount of thought.