The pilots of these vehicles seem to have subterranean bases all over the world, and even some under bodies of water and in the oceans. Anywhere where there are lots of disturbances such as Skinwalker Ranch and the Bermuda Triangle are usually suspect, because the UFO tech and other energy tech seems to allow for time distortions. It could be that the UFOs are capable of time travel, so when a plane, for example, goes missing in the Bermuda Triangle it could be that it’s be sucked into a time vortex and transported into either the past of the future. The Lochness Monster might be a dinosaur that randomly wandered into our time, and so could Sasquatch. It’s not uncommon for people to go missing in national forests either, and yet their remains and belongings occasionally will eventually show up randomly in places a search party has already initially combed over several times.