In February 1945, a small group of personnel assigned to the Office of Strategic Services, the wartime spy agency, scrambled to prepare for a particularly risky mission: inserting a team of agents deep behind Nazi lines with the goal of gleaning crucial enemy information.

For a host of reasons, the proposed operation seemed like a suicide mission. The area targeted for dropping the three-man team into Nazi territory was high in the Austrian Alps, surrounded by towering peaks and flanked by antiaircraft weaponry. Even if the drop went as planned, some of the spies tapped to infiltrate enemy ranks were European-born Jews, increasing the dangers they faced.

After the Royal Air Force refused the dangerous mission, code-named Operation Greenup, John Billings, then a lieutenant in the U.S. Army Air Corps, was given the job. Assigned to the 885th Bombardment Squadron, a special unit tasked with risky, low-altitude missions in support of Allied spies, Billings was already a combat veteran, having flown close to 15 daylight strategic bombing missions.

Billings and other veterans who made possible some of World War II’s most daring spy missions were among those honored this weekend by the OSS Society, a group that includes former OSS members and members of the U.S. intelligence, military and Special Operations communities.

To succeed in the nighttime mission, Billings would have to navigate his B-24 Liberator between Alpine peaks to a drop area on a frozen lake. The lake was perched at about 10,000 feet, in a valley that emptied into the Brenner Pass, a valley linking Austria and Italy. The area was seen as so important that Nazi forces had placed antiaircraft weapons at the top of the pass so they could fire down on Allied aircraft. Billings had flown in the area before, usually keeping close to the ground to evade radar detection.

As the team approached the target zone that night, the plane was buffeted by severe downdrafts, dropping 6,000 feet in 20 seconds. Billings, speaking by phone from his home in Woodstock, Va., called the drop “exciting.” But it was sufficient time, he said, to adjust his instruments and keep the plane aloft. “They say when you’re in a critical situation time stands still for you,” he said.

Billings was able to position the three-man spy team for a safe jump, from about 300 feet above the frozen lake. Once on the ground, the team, led by a German-born, naturalized American named Frederick Mayer, headed toward nearby Innsbruck. The team also included a Dutch-born Jewish man named Hans Wynberg, whose family had been sent to Auschwitz, and a disaffected Austrian officer named Franz Weber.

Once in place, Mayer posed as a German army officer and conveyed information about Nazi movements toward the end of the war. In later interviews, he said he was motivated to join the military out of a desire to act personally against the Third Reich. “It felt like I had my chance to do what I set out to do — kill Nazis,” Mayer said in a 2012 television film titled “The Real Inglorious Bastards.” “That’s why all the Jewish boys joined.”

In addition to Billings, Gaetano Rossi and Caesar Daraio, two then-sergeants who were part of operational groups made up of Italian American volunteers, were honored with OSS Society awards for their work advancing the Allied cause during World War II. Also honored at this year’s “spy ball” was David Cohen, who served as director of operations at the CIA and as a senior intelligence official with the New York City Police Department, and retired Gen. Norton A. Schwartz, former Air Force chief of staff.

The OSS Society is advocating passage of a proposed measure that would honor the wartime spies, which so far has not gained required congressional support. The proposal, which would award living OSS veterans the Congressional Gold Medal, has stalled in the House.

After retiring from the military as a captain, Billings became a commercial pilot. At age 93, he still pilots a Cessna Cutlass. Most of the time he flies “angel flights,” transporting people in need of medical attention.