Finland — One week after U.S. fighter jets intercepted Russian bombers approaching Alaskan airspace, American and allied warplanes are sending a message to the Kremlin. They're taking part in aerial military exercises in the Arctic Circle, a remote part of the world where Russia has been flexing its muscles.

Recently, F-18's from U.S. Marine Fighter Attack Squadron 251 soared into the skies, alongside jets from Finland and Denmark. They took part in war games against an "imaginary" enemy, right on Russia's doorstep.

For one exercise, Lt. Col. Roy Nicka and his team played that imaginary enemy. CBS News had the rare opportunity for a ride along. The mission was to penetrate allied air defenses, viewed from the cockpit of one of the most capable jet fighters in the world.

After a steep climb, there was a refueling stop with a British tanker. France, Germany, Sweden, Norway and the Netherlands were also in the sky. There were some 140 aircraft and more than 1,000 personnel.

"It's a deterrence exercise. Again, it's making sure that Russia, we know that Russia's going to watch," said U.S. Marine Maj. Gen. Russell Sanborn. "If they are watching, I imagine the thought process in their head would be 'Wow, nobody's going to come at us alone, they're going to come at us as a coalition.'"

Russia has already responded, with increasing aggression. Norway accused Russia of jamming communications systems during NATO exercises in 2018 and launching dummy aerial attacks in 2017.