U.S. and Canadian air forces have scrambled jets twice over the past week to intercept Russian aircraft that have buzzed the Alaskan and Canadian coastlines twice in the past week.Listen now: A U.S. F-15 out of Elmendorf Air Force Base (before it was re-named Joint Base Elmendorf Richardson) escorts a Russian Tu-95 Bear bomber out of Alaska airspace in 2006. Credit Wikipedia.orgThe latest round in the cat-and-mouse game between U.S. and Russia aircraft played out a week ago over the waters off Alaska’s northern coast. Late Wednesday, the Air Force scrambled two F-22s from the 3rd Wing at Joint Base Elmendorf-Richardson to intercept six Russian military aircraft that were flying within 55 nautical miles of the Alaska coastline.The two Mig-31 jet fighters, along with two long-range bombers and two refueling tankers, didn’t enter U.S. airspace, only the U.S. Air Defense Identification Zone.A few hours later, another pair of the long-range bombers Russian bombers flew within 40 nautical miles of Canada northern land mass on Thursday. The pair of turned back after being intercepted over the Beaufort Sea by two Canadian F-18s.Both times, the Tupolev bombers didn’t enter either U.S. or Canadian airspace during what Moscow has long referred to as “training flights.” The aircraft only entered the Air Defense Identification Zones, or ADIZ, which extends about 200 miles north off the coast of both the United States and Canada.“Russian long-range aviation flights have, for instance, have entered our ADIZs, but not our sovereign airspace. These flights are perfectly legal, and we do not consider them threatening or provocative. When we intercept and identify their aircraft, both sides have exercised professional airmanship in all cases.”Nahom talked about U.S. and Russian aircraft encounters during a visit in May by Defense Secretary Chuck Hagel. He left the 3rd Wing at Joint Base Elemendorf-Richardson last summer to take a new position back in Washington, D.C.Based on Nahom’s comments, the Wednesday’s interdiction played out as it usually does, the Russian bomber pilots execute a turn away from the mainland after the U.S. warplanes show up.“They seem to be pretty constant. Over the past few years you average 10-12 of such flights inside of our ADIZs per year. We have F-22s that sit alert here at JBER and when someone starts approaching the ADIZs we do scramble out to meet ‘em and make sure they don’t go any further in approach to U.S. airspace.”The Toronto Globe and Mail says U.S. and Canadian warplanes have intercepted about 50 Russian aircraft over the past five years.But the Christian Science Monitor reports that a North American Aerospace Defense Command spokesman said Friday that the flights are part of an increase in such activity near the Alaska air defense identification zone.The Globe and Mail, the Monitor and several other news media noted that U.S. officials believe the two incidents were linked to Ukrainian President Petro Poroshenko’s visits last week to the United States and Canada.