BANGOR — Each day, everything from guns and ammunition to food and medical supplies travel along the military’s “air bridge” between the United States and Europe, Iraq, and Afghanistan.

National Guard and Reserve units in Maine, New Hampshire, New Jersey and Pennsylvania with special skills in refueling planes in midair keep the vital traffic flowing both ways across the Atlantic Ocean. But the Air Force, under a budget-cutting directive, is considering dismantling the program.

More than 400 personnel in five units in the four states have been notified they may be required to stand down at month’s end as the Air Force considers reallocating resources.

The Air Force is trying to reduce the number of days worked by Air National Guard personnel by 20 percent, said Sen. Susan Collins, R-Maine. But the program cuts make little sense, she and other critics say, because it would cost more in jet fuel and flying time to bring in active-duty Air Force units from farther away.

“This is a clear example of the right hand not knowing what the left hand is doing,” Collins said. “The budget side is saying, ‘We need to reduce costs.’ Then those who’re responsible for the mission are saying, ‘Wait a minute. Who’s going to refuel these flights?’ It’s just incredible.”

The Air Mobility Command, based at Scott Air Force Base, Ill., is reassessing active Guard and Reserve needs for the new fiscal year, said AMS spokesman Lt. Col. Glen Roberts.

The so-called “air bridge” went into action in 2003 as the military began a buildup of troops and equipment for what became the war in Iraq. As the war continued, so did the mission.

The 101st Air Refueling Wing in Bangor has played a prominent role in moving supplies and even injured soldiers because of its strategic location as the last U.S. base for outgoing flights and the first for flights incoming.

“We’re fighting the war from our own backyard,” said Col. John D’Errico, commander of the 101st wing, which has 150 military personnel devoted to the air bridge program.

Aerial refueling is used when the military wants critical flights to get to a destination in a hurry. In those instances, aircraft can take on fuel while flying in tandem with a refueling tanker at more than 400 mph. The refueling tanker can carry more than 85,000 pounds of fuel.

About 1,000 planes in the past year have received jet fuel in this way under the air bridge program, officials say.

Bangor-based KC-135 tankers can reach their primary refueling route – over Nova Scotia – in just 18 minutes, said Col. Gerard Bolduc, the 101st vice commander.

Their proximity saves $2,000 to $8,000 in fuel per sortie, he said.

“The cost would be astronomical to fly these same missions out of active-duty bases,” said D’Errico, noting that most active-duty bases flying tankers are in the Midwest.