OVER THE PACIFIC OCEAN (AP) — A groundbreaking international training exercise will make it more difficult for terrorists to pull off a hijacking against the U.S., Canada or Russia by "hardening" the air travel system against attacks, a Canadian officer said.

The exercise is scheduled to wrap up Tuesday in Anchorage, Alaska, after fighter jets from Russia and the North American Aerospace Defense Command chase a chartered jet playing the role of a hijacked commercial airliner flying east across the Pacific.

The exercise is designed to test how well civilian and military aviation authorities on both sides of the ocean can coordinate their efforts during a hijacking, especially during the critical handoff stage when the commandeered plane moves from Russia's airspace into the territory defended by NORAD, a joint-U.S.-Canada command.

"I think any time that we increase our cooperation and our coordination, we harden ourselves against further events," said Canadian Forces Col. Todd Balfe, the deputy commander of NORAD's Alaska region and the senior NORAD observer aboard the "hijacked" plane — actually a high-end Gulfstream passenger jet.

"If, for example, we make it harder for terrorists to do us harm, they'll choose either not to do us harm or will look for other, more difficult manners or other ways of approaching us," Balfe said.

If terrorists do succeed in hijacking a plane, the exercise will help NORAD and the Russians be prepared to respond.

Military commanders and civilian analysts say the threat of terrorism is serious for the U.S. and Russia. On July 29, a man seized a plane with 105 passengers and crew at a Moscow airport. On Christmas Day, a Nigerian man allegedly tried to blow up a jetliner over Detroit.

The joint exercise, called Vigilant Eagle, began Sunday when the Gulfstream, code-named Fencing 1220, left Anchorage and headed west.

Along with Balfe, Russian Air Force Col. Alexander Vasiliev, U.S. Army Maj. Michael Humphrey and a U.S. translator were on board. The Associated Press had exclusive access to the Gulfstream on both the westbound and eastbound flights.

Shortly after takeoff, the Gulfstream's civilian pilots sent a digital distress code to civilian air traffic controllers in Alaska signaling it had been "hijacked."

Civilian controllers notified NORAD, which dispatched two F-22 Raptor fighter jets to shadow Fencing 1220 and an E-3 Sentry airborne surveillance and control plane to track it.

When the Gulfstream entered Russian airspace over the Pacific, commanders in the E-3 handed over responsibility for the plane to their Russian counterparts on an A-50 Mainstay surveillance and control plane. Four Russian Su-27 fighters and one MiG-31 took turns shadowing the Gulfstream.

On the return trip, the process will be reversed, with Russian fighters and surveillance planes shadowing Fencing 1220 for the first portion before handing off responsibility to NORAD.

A detailed evaluation of the exercise is planned in September.

Balfe said it has already succeeded on one of its goals — a smooth handoff from NORAD to the Russians.

"I expect to hear the exact same thing but in reverse" when the Russian controllers turn the chase over to NORAD on the return leg, he said.

All three observers aboard Fencing 2012 — Russian, American and Canadian — marveled at the historic nature of the exercise, which demanded a level of cooperation that was unthinkable during the Cold War standoff between the U.S. and its allies and the Soviet Union, Russia's predecessor.

Vasiliev said he always thought the time would come when the two former enemies would work together, but he said he never expected to be Russia's representative. Humphreys said the Russian fighters cruising alongside Fencing 1220 was an incredible sight.

Balfe called the exercise "a watershed moment."

"If I'd been told 20, 25 years ago I'd be sitting on a U.S.-registered airplane with a Russian colonel as my counterpart, going over through Russian airspace on this exercise, I'd have thought you were crazy."


Associated Press photographer Ted Warren contributed to this report.