The question of whether these are terrestrial or extraterrestrial in origin frequently comes up with most people believing we were incapable of creating craft with these performance characteristics. However, I have been told they are of terrestrial origin.
An X-coworker was in the national guard reserves. Once weekend each month he maintained electronics on these craft. He explained to me what they were, why they were created, and how they operate.
They are a nuclear fission powered aircraft with an infrared sensor bank and nearly infinite hover time.
They were created to monitor Soviet nuclear launches. Cloud cover frequently obscured satellite vision. Spy planes couldn’t remain aloft over Soviet territory for more than a couple of hours at best. A craft was needed that could hover and remain in place for long durations.
An aircraft relying on petroleum based fuel can’t carry enough fuel to remain aloft very long. Nuclear fission was a potential solution. However, earlier attempts at nuclear craft based on nuclear jets, Prometheus in particular, were dismal failures.
This craft is based upon an entirely different principal. It has an on board nuclear fission reactor similar to what you might see in a nuclear submarine.
This craft operates on the same principals as an MHD powered submarine, except since air is not normally conductive like seawater, it uses three plasma torches to ionize the air so it can then be directed by a magnetic field to provide propulsion. So instead of magneto-hydro-dynamics, you have magneto-plasma-dynamics. The same exact principals apply.
There are three plasma torches and jets, one at each point of the triangle, this forms a stable platform allowing the craft to hover a long time.
The magnetic coils used to propel the plasma are superconductive. It happens that the craft is also fitted with an infrared sensor array underneath so it can spot nuclear missile launches. The array requires cryogenic cooling, so do the superconductive coils, so one refrigeration system can do double duty.
I understand the infrared censors are also good at spotting marijuana on public and and that they
have been using it for that purpose as well.