Trajanus

Was there any communication with the aliens encountered?

I agree absolutely. Of course the UFO phenomenon is perfectly consistent with the prediction that alien life exists. It's the answer to the Fermi paradox. If ET exists why aren't they here? They are.

There is a great variety of reported beings but most probably aren't genuine in the sense of being naturally evolved. At least one work, The Alien Grand Design, opines that many are artificial creations for specific missions.

I don't buy it. Homo erectus was more closely related to modern humans.

There are a number of possibilities. The late Robert Morrison suggested Gravitational Field propulsion. I wouldn't say their technology is totally beyond our comprehension, though they're still well ahead.

The ETH always made certain predictions such as extrasolar planets exist in large numbers. That is certainly confirmed. For decades people have seen unusual flying objects apparently technological yet with appearances and flight performances unlike anything from Earth. In addition, there have been many sightings of UFO occupants who appear unlike humans. Put two and two together. :)

Grusch wrecked his own credibility by accepting the specious 1933 Italian crash case. Like many others his apparent mission was to spoil the crash retrieval field.