James Goodson, an American-born ace during World War II who was credited with 15 aerial kills and 15 strafing ground kills, died May 1 at 93. (U.S. Air Force)

James Goodson wanted to see the world in the summer of 1939, so he boarded a ship and made his way across the Atlantic to Europe by working as a pantry boy.

A few months after Mr. Goodson arrived, Joseph P. Kennedy Sr., the U.S. ambassador to England, urged all American expatriates to return home because of the looming threat of war.

Mr. Goodson, who died May 1 at 93, booked passage on one of the last ships to leave England before Europe convulsed into world war. The vessel was the ill-fated liner Athenia, which on Sept. 3, 1939, was torpedoed and shelled by a German U-boat off the Scottish coast.

More than 100 of the roughly 1,300 passengers and crew members perished before rescue boats arrived. Mr. Goodson and other survivors were taken to port in Galway, Ireland, where children from the ship wept for their missing parents and many adults were inconsolable. One woman said she saw two children fall from a lifeboat as it was lowered into the chilly water. They were never seen again.

Mr. Goodson was on the Athenia’s deck when the torpedo struck, and he recalled assisting with rescue efforts as the ship listed and its lights went dark.

James Goodson in his cockpit. He shot down 15 German planes in the air and destroyed another 15 on the ground. (U.S. Air Force)

“I went to see if there were people trapped in the main section, and I saw dead bodies swooshing around in the water,” he later wrote. “I was plunged into the whole war thing, if you like, in a matter of minutes. I suppose Americans looked at the European war as something that didn’t much concern them.”

The sinking of the Athenia — an early victim in the Battle of the Atlantic — helped turn world opinion against Germany. For Mr. Goodson, it was the moment when he decided to do his “bit to stamp out Nazism.” He went on to become a leading Army Air Forces ace in the European theater, with 15 aerial kills and another 15 strafing kills of enemy aircraft on the ground.

His success brought him the nickname “King of the Strafers,” said Roy Heidicker, an Air Force historian.

After the war, the newly formed Air Force counted only air-to-air victories in tallying aces. Francis S. Gabreski, with 31 kills (including three on the ground), was the leading Army Air Forces ace in Europe during the war; Richard Bong, an Army Air Forces pilot in the Pacific, was the highest flying ace overall, with 40 hits.

Mr. Goodson, who was American-born and was raised in Toronto by British parents, had been among the first U.S. volunteers to enlist in Britain’s Royal Air Force. He initially flew in one of three “Eagle” squadrons, RAF units made up of American pilots. By the summer of 1942 — many months after the United States entered the war — the Eagle squadrons were incorporated into the 4th Fighter Group of the U.S. Army Air Forces.

Mr. Goodson recorded two kills as an Eagle squadron member, but he had his best-known exploits with the 4th Fighter Group under the hard-driving, taciturn commander, Donald Blakeslee.

During Blakeslee’s tenure, the 4th Fighter Group racked up one of the most remarkable records of the war, destroying a total of 1,016 enemy aircraft on the air and on the ground, Heidicker said.

By the fall of 1942, the 4th Fighter Group represented the only operational American fighting units in Europe. Mr. Goodson conducted one of the first American-led, low-level strafing sorties over France and Belgium, a two-man, two-plane mission.

He and his partner considered the results to have been modest. But military publicists, looking for scraps of good news, trumpeted the affair as “the first U.S. fighter raid over the Continent” and “daring low-level attacks on rail, road and water transport in Northern France and Belgium, leaving behind them a trail of destruction.”

He received the Distinguished Service Cross — the military’s highest award for valor after the Medal of Honor — for his actions as a P-47 Thunderbolt pilot on March 16, 1944, while escorting U.S. bombers in a raid over Berlin. In Germany, he encountered an overwhelming number of enemy Messerschmitt Bf 109s trying to pick off the bombers.

According to the award citation, Mr. Goodson dived after the Messerschmitts and knocked out two while weaving in and out of the line of fire.

That June, he was in his P-51 making a strafing run over a German airfield when he was shot down. He fled into a birch forest before collapsing from injuries. He eventually was caught by the Germans and threatened with execution.

He recalled that one captor asked him if he wanted a drink or another indulgence before being shot. Mr. Goodson spied a box of Havana cigars, asked for a stogie and began to blow smoke rings, which he said shocked the German and led to a conversation about their mutual interest in cigars.

“The guy had never seen anything like that,” Mr. Goodson once said in an interview, “and I started teaching him how to blow smoke rings.” Instead of being shot, he was sent to a prisoner-of-war camp.

“People say smoking costs lives,” he said. “It saved my life.”

James Alexander Goodson, known as “Goody,” was born March 21, 1921, in New York City. In Toronto, he was studying languages when he set out for Europe.

After being held at POW camps in Poland and in Germany, he was repatriated in April 1945. His honors included the Silver Star, nine awards of the Distinguished Flying Cross, the Purple Heart and 21 awards of the Air Medal. He retired from the Air Force Reserve with the rank of lieutenant colonel.

Following his wartime discharge, Mr. Goodson became an executive with Goodyear, Hoover and the conglomerate ITT. He wrote a memoir, “Tumult in the Clouds,” published in 1983.

His wife of 62 years, the former Gwendolyn Rice, died in April. Survivors include a son, James Goodson Jr. of Marshfield, Mass.; and three grandchildren.

Mr. Goodson had pneumonia and died at a hospital in Plymouth, Mass., his son said. Mr. Goodson was a resident of Duxbury, Mass.

He once told the Boston Herald that, as a POW, he was visited by a group of German aces in a display of respect. “It was a different time,” he said. “That’s all gone now.”