The Montana Air National Guard went back to the future on Friday — at about 450 miles per hour — when two 30-year-old model F-15s touched down on Gore Hill, officially signaling the start of the MANG's new mission.

While the F-15s are eight years older than the F-16s flown for 22 years by the 120th Fighter Wing, they have a longer lifespan and should extend the mission life, said Maj. Ricky Anderson, chief of public affairs for the wing.

The decision to change aircraft was made by the 2005 Base Realignment and Closure Commission at the request of the Pentagon, which originally wanted to eliminate flying missions at several Guard units nationwide.

BRAC reversed that decision after concluding it could impact local Guard sites and recruitment, instead choosing to take advantage of Montana's largely uncluttered airspace by assigning the F-15s to the 120th Fighter Wing.

Lt. Col. Darrin Barritt of the Missouri Air National Guard was one of the pilots who brought the first two F-15s here Friday.

"It's been my life for 21 years," Barritt said after climbing out of the jet. "It's a great machine."

The F-15 is 15 feet longer, 12 feet wider and 2 feet taller than the F-16. The twin-engine F-15 also is capable of faster speeds and higher altitudes than the single-engine F-16.

The F-16 Fighting Falcon was designed to be a dual-purpose fighter, capable of engaging air and ground targets. The F-15 Eagle models that the Montana ANG will fly are exclusively air-to-air fighters.

"We shoot down other airplanes," Berritt said.

Maj. Kelly McCoy of the Montana ANG has flown both fighters.

He said that the main difference, besides size, is the enhanced radar capability of the F-15.

"The entire airplane was basically built around the radar," the commercial airline pilot said in a telephone interview from Alaska.

He said the Montana ANG's pilots will have to learn the F-15s controls. Both jets have a hands-on control system, meaning nearly every finger has a button or switch nearby that controls something on the plane. A fighter pilot often relies on muscle memory to know that the right index finger is responsible for turning a certain device on or off. While both jets have this type of control system, the functions of specific buttons and switches are completely different, McCoy said.

"You have to step back a bit. ... You have to learn what your fingers have to do," he said. "It takes a while to get the old habits out."

From a maintainer's standpoint, the F-15s feature less electronics and more hands-on work. Instead of a computer troubleshooting every issue, the maintainers will have to hunt for it, said Staff Sgt. Doug LaPierre, who has worked on both planes and prefers the F-15 for that reason.

"They're kind of a dinosaur in the fighter aircraft world," he said, adding he missed the aircraft when he moved from Oregon to Great Falls, switching Guard units in the process.

"When I heard we were gonna get these — I was ecstatic," he said after hooking up a tow vehicle to the parked planes Friday.

While the Montana ANG's pilots and maintainers previously said they'll miss the F-16s, which already were sent to the Vermont Air National Guard, Barritt said he feels the same way about the F-15 as his Guard unit coverts to B-2 bombers.

"The final (F-15) flight hasn't come yet — it will be a sad day," Barritt said. "I'm bummed out."

The Montana ANG will receive two more F-15s on Aug. 22, then two a month until the full fleet of 18 is at Gore Hill. The fighter jets are coming from the Missouri ANG and Eglin Air Force Base, Fla.

Residents can expect to see the F-15s regularly in April, once the 120th Fighter Wing's pilots and maintainers complete their training on the older aircraft.