https://dronemadness.com/wp-content/uploads/2019/02/Gas-Powe...
And the secon possible is the Unihawk family from Efy Tech
https://www.efy-tech.com/en/file/upload/2019/06/11/156040236...
Also not sure how they were confident enough to deduce it was a drone. Clearly it was like 1000-1500 feet above them in dark.
We just chose to call a UFO a UAV. That's what I learned from the article.
Or.
May be it was just a test. They wanted to see how people would handle a situation like that.
"intimidate a power like US" is what China, and Russia are doing with monthly regularity around the world with zero pushback.
The only time ever USA gave a direct response was this https://en.wikipedia.org/wiki/Battle_of_Khasham and even that was made more out of fear than a deliberate pushback, despite it sending kremlin into weeks long stupor.
[1] https://en.wikipedia.org/wiki/List_of_United_States_military...
Looks like an unashemed intimidation operation, given that there is nowhere in Guam a civilian can bring a car sized quadcopter, and island's tiny population.
It pretty much screams of somebody trying to say "we can fly our foo-drones over your missile battereys, and ship any time"
Of all countries, there is only one on record with car sized, gas powered quadcopters.