=)

The trick here is that most of the sightings are by air force pilots, so not much about landing gear or say beings (if any) who are inside them. (I say "if any" because why wouldn't they be drone-operated since we have those anyhow?)

According to Corey Goode, the alien greys ARE infact, a sort of drone. everyone uses them in the Galactic council: The Mantids, the Tall greys, the half orcs, the triangle heads... those that can't do everything with their awesome psychic powers that is.

There was sound logic at work. Tripods, like three-legged stools, are never out of balance.