Flew into civilian airzone with transponders turned off and could not be tracked by civilian traffic control
Here's news that went largely unreported in the west. Straight from the US government-funded Radio Free Europe:
Russia said it summoned a U.S. defense attache on May 23 after an American military aircraft flew into civilian airspace during a reconnaissance mission near Russia's far-eastern border.
Russia's defense ministry said that the U.S. Air Force RC-135 surveillance plane risked colliding with passenger planes as it flew over the Sea of Japan on May 22 because it had turned its transponders off and could not be detected by civilian radar, although it was flying at an altitude typically used by passenger jets.
The U.S. crew did not inform regional authorities of the plane's route, said the ministry.
"The U.S. plane crew's unprofessional actions created the danger of a collision with...civilian airlines," the ministry said, adding that measures must be taken to prevent such incidents in the future.
Potentially endangering civilian air traffic is bad enough, as is harassing Russia which constant surveillance flights just at the tip of its border. Combining the two is absolutely scandalous.
Imagine if a Russian military plane had strayed into civilian air zone off the coast of Florida but kept its transponder off. In such a case the media would quite rightfully shred Kremlin to bits. Alas it was actually the Americans and therefore there is not even a whimper.