"They've been flying periodically since then with a good bit of activity over the past few weeks," says Gene Renuart, commander of the North American Aerospace Defense Command (NORAD).
The prospect of a Russian attack may seem far-fetched, but General Renuart, who is responsible for defending the U.S., says in a world where every airplane is a potential threat he has to scramble the jets - and all the airborne radar and refueling tankers it takes to support them.
"Any time you have an unidentified aircraft approaching sovereign air space of the country there's some concern about the intentions of the airplane," Renuart says.
No one thinks the bombers signal a resumption of the Cold War, but Russia feels it's being treated like a second rate power and relations are starting to get a little chilly.
"Russia is willing to assert itself and is looking for a whole variety of ways to show to the United States that Russia is back as a serious power," says Dimitri Simes of The Nixon Center.
Simes sees the bomber flights as the military equivalent of Russian President Vladimir Putin bearing his chest for the cameras. It's a pattern of posturing that includes Russia's claim that it has developed the most powerful non-nuclear bomb in the world. Never mind that U.S. intelligence says the bomb represents old technology and that the video of its testing was probably shot years ago.
"There is a perception in Moscow that Russia is being taken for granted," Simes says, "and they want to put an end to this."
President Bush has noticed, sending his two top cabinet officers to Moscow this week to address a growing list of disagreements.
As for those bombers, General Renuart asked the Russians if they could at least file a flight plan. So far there has been no response.