How is that Occam's Razor? This is the same guesswork as aliens or foreign countries. I just see a lot of people using "Occam's Razor" with their subjective theories and the term is giving me a headache.
Occaam's Razor claims that terrestrial technology is more likely than extraterrestrial because it relies on fewer unproven assumptions, namely the existence of extraterrestrial life, its presence on Earth, and everything we know about physics being wrong, despite the math somehow working out to describe the universe incredibly well.
That said I think there are other alternatives that are even more likely: that these sightings are sensor malfunctions or natural phenomena that have been blown out of proportion by popular myth and deliberate disinformation -- (which is certainly the case with all other UFO sightings).