Why is it that we should consider this an act of war. A drone is no different than a missile. Its a hunk of metal. It has no more moral authority than a cannon ball. If it is interfered with, take it up with the world court. If you shot it into Russian airspace you can best believe they will shoot it down straight away.
If there was a person strapped to it. Thats a different story. They will try to capture him alive and figure out what he is doing. Then after some roughing up, they will hand him back in their time.
Who in the US is saying this is "an act of war"? Provocation, yes.
Milley Won't Call Russia's Downing of U.S. Drone an Act of War