NATORI, Japan >> Last month, when a team of U.S. Air Force Special Operations forces reached the damaged Sendai Airport, just a mile from the coast, it found a devastated landscape of uprooted buildings, smashed vehicles and the bodies of the dead.

Using skills honed in war-torn nations like Iraq, the airmen had within hours cleared part of a runway for use by U.S. military aircraft. Over the next four weeks, they worked to restore Sendai Airport, where the huge tsunami had flooded the runway and threatened to engulf the sleek glass terminal.

On Wednesday, the airport in Sendai, one of northern Japan’s largest cities, nearly 200 miles northeast of Tokyo, reopened to commercial flights for the first time since the earthquake and tsunami struck on March 11. But when the airport resumes civilian operations, the two dozen members of the Air Force unit, the 353rd Special Operations Group, will not be on hand to celebrate. Nor will most of the 260 Marines and soldiers who also joined the cleanup.

They will have already packed up and gone. Their absence reflects the balance the U.S. military has tried to strike in Japan, where it has undertaken one of its largest relief operations, while also being careful not to be seen as taking a role that might upstage its hosts.

“Our goal is for no one to notice that we were even here,” one of the 353rd’s members, Maj. John Traxler, said last week. At that time, he was directing taxiing aircraft with a radio on his back because the control tower was still under repair.

This is not to say that the U.S. military has shied from trumpeting its sweeping aid operation, involving 18,000 people and 20 ships, including the nuclear-powered aircraft carrier USS Ronald Reagan. The Pentagon has dubbed it Operation Tomodachi, Japanese for “friend,” reflecting its goal of fostering good will in a nation that hosts 50,000 U.S. troops.

But this is a proud country that can grow touchy over the presence of the U.S., which occupied Japan after World War II and helped configure its reborn military as a nonaggressive force limited to national security and self-defense. So U.S. commanders have been careful to stress that they are in a supporting role, even in places like Sendai, where they were instrumental in fixing the airport.

“We are used to doing this in third-world countries, where we have to come in and do it all,” said Col. James Rubino, commander of a Marine Corps logistics unit camped in tents on a Sendai Airport parking lot last week. “Here, we make sure the Japanese government and Self-Defense Force have the lead.”

Rubino said that in a less developed nation, like Haiti or Indonesia, thousands of Marines would have been sent in with trucks, heavy equipment, their own engineers and medical staff. Here, he said, the Americans limited themselves to a skeleton crew of 260 Marines and soldiers who used two dozen trucks and construction vehicles to clear the airport and unload relief supplies.

“There are concerns about us upstaging the Japanese Self-Defense Forces,” Rubino said.

Near his unit’s tents, a small outfit of Japanese construction workers was at work washing away mud, rewiring lights and even using a small bulldozer to scoop out debris from the baggage claim room.

The situation was quite different after the Kobe earthquake in 1995. Then, Tokyo rejected assistance by the U.S. military, a decision that many Japanese criticized for possibly raising the death toll. This time, Tokyo accepted, and promptly.

“It was amazing how quickly they could come in and move the debris and broken cars,” said Col. Makoto Kasamatsu of the Self-Defense Force.

Kasamatsu leads a small group of Japanese soldiers who serve as coordinators between the Americans and the civilian airport authority, which is officially in charge of Sendai Airport and has also played a large role in the cleanup.

Within minutes of the 9.0 magnitude earthquake on March 11, some 1,400 passengers and workers in the terminal suddenly found themselves surrounded by black, churning waves that crumpled parked aircraft like paper toys.

The people were rescued, but the airport seemed a near total loss — until Col. Robert P. Toth, commander of the 353rd Special Operations Group, based in Okinawa, heard of the airport’s destruction. His unit specializes in turning ruined landing strips and patches of empty desert into forward supply bases for U.S. aircraft, but usually in war-torn countries, like Iraq, Somalia and Afghanistan.

“It was clear that opening Sendai Airport was the No. 1 priority, but everyone had written it off,” Toth said. He approached his superiors with a plan to turn it into a hub for U.S. relief.

He said when the unit made an initial helicopter survey the day after the earthquake, the airport was still under 8 feet of water.

When the unit arrived three days later, driving in on Humvees that been flown to a Japanese air base a few hours away, the first task was clearing enough of the runway for aircraft to land. In the following weeks, the Americans and Japanese moved more than 5,000 cars that had been washed onto the runway by the waves, lining them up in neat rows along the edge of airport.

When they found bodies, they called over Japanese crews. They would not say how many bodies were found, out of respect for Japanese sensitivities.

With the control tower damaged by the waves, the U.S. ran the airport for weeks, guiding their military planes in and out from backpack radios. Ahead of Wednesday’s reopening, control was slowly restored to the Japanese.

Since March 15, Toth said the Americans had used the airport to distribute more than 2 million tons of food, water and blankets.

“This is what we do: look for a disaster, and set up a runway,” said the Air Force’s Traxler. “But I have never seen this level of devastation, not even in combat.”

© 2011 The New York Times Company