For Jimmy Doolittle's co-pilot, taking off from an aircraft carrier, flying hundreds of miles and bombing Japan was the easy part of the daring 1942 American air raid on Tokyo.

The worst moment came hours later, when he had to parachute out of his B-25 bomber over China in the middle of a heavy storm.

"That was the scariest time," said Richard Cole, now 98 years old.

"There you are in an airplane over a land you are not familiar with, under a big weather front, very active with lots of rain, with thunderstorms and lots of lightning and you are going to jump out," he said.

"There are lots of questions that are going through your mind."

Out of the 80 men who took part in the storied Doolittle raid that boosted America's morale in the early days of World War II, only four are still alive.

Cole and two of his fellow veterans, also in their nineties, attended a "final reunion" Saturday at the US Air Force's National Museum in Dayton, Ohio.

In a ceremony webcast live and attended by family and dignitaries, the three elderly men toasted comrades who have died since the raid, as well as the five airmen who perished in the operation.

"Gentlemen, I propose a toast to those we lost on the mission, and those who have passed away since: thank you very much and may they rest in peace," Cole said, as he and his fellow veterans raised goblets of cognac.

The Doolittle crews "inspired a nation," Air Force chief General Mark Welsh told the veterans, and "you turned the tide of a war."

The raid has been immortalized on screen and in numerous books, but Cole said he never expected the operation would take on so much importance.

"I never dreamed this thing would last so long and that so many people would be interested in it," he said in a telephone interview with AFP.

The bold operation was led by Lieutenant Colonel Jimmy Doolittle, who became an American hero after 16 B-25 bombers under his command struck Tokyo five months after the Japanese decimated the US Navy at Pearl Harbor.

When he volunteered for the top-secret mission, Cole knew it would be dangerous but he only learned of the target aboard the carrier USS Hornet in the Pacific Ocean.

Once the crews were told they would be attacking Japan, there was "a lot of jubilation," he said. "But then it became kind of quiet because people were realizing what they were going to be doing."

The assault was close to a suicide mission.

The plan called for the aircraft -- which had never seen combat -- to fly over Japan with no fighter escorts and then head towards eastern China, where homing beacons would supposedly guide them in for a landing.

After their carrier was spotted by a Japanese vessel, Doolittle decided to launch the raid immediately, 10 hours earlier than scheduled and 650 nautical miles (1,200 kilometers) from Japan.

The aircraft took off on April 18, and arrived over Japan six hours later, achieving total surprise.

"We were not jumped by any kind of a fighter or other airplane," Cole said. "We went across at Japan at low altitude. We could see planes above us and apparently they couldn't see us."

After a bombing run that lasted only a few minutes, the B-25s got "the heck out of there."

As they flew toward China, the navigator passed a note up to the cold, noisy cockpit. They would run out of fuel 180 miles (290 kilometers) short of their destination, the note said, meaning the plane would have to be ditched at sea.

A strong tail wind, however, "pushed us all the way to China," Cole said.

They arrived on the coast at dusk, but a planned homing signal to help them land never appeared.

So they flew until their fuel tanks were empty and parachuted out.

Cole's chute got caught in a tree. In darkness and pouring rain, he opted to stay atop the tree until daylight.

"After that, I climbed down and started walking west with my compass.

"And after walking all day, I came on to a paramilitary compound and was taken in by the Chinese, who were very helpful."

He and his crewmates were eventually reunited and flown out on a US aircraft. But all the B-25s were lost in the raid, and Doolittle worried he would be court-martialed.

Although the bombing caused only modest damage in Tokyo and elsewhere, the attack's psychological effect -- in Japan and the United States -- was dramatic.

Americans felt they had scored a counter-punch, and an embarrassed Japan soon launched an unsuccessful naval attack at the Midway Atoll that proved a turning point in the war.

It would be more than two years before US aircraft bombed Japan again.