On the day that should have been Aharon Steinberg’s bar mitzvah, he was in a bomb shelter in the Tel Aviv suburb of Ramat Gan.

He turned 13 in 1967, during the Six-Day War. All the men in town had been called up for reserve duty. Young Aharon never got to chant his bar mitzvah portion, Baha’alotecha. The party that had been planned was cancelled.

Nearly 51 years later, Mr. Steinberg, a long-time resident of Ringwood, unexpectedly had his long-overdue bar mitzvah ceremony aboard an El Al plane. The plane was en route from Poland to Israel, carrying 150 members of the Friends of the Israel Defense Forces’ “From Holocaust to Independence” mission, as well as 50 IDF soldiers and officers.

As they boarded the plane in Poland on April 16, the participants’ mood was somber. They had toured tragic landmarks, including Krakow, once home to a flourishing Jewish community of 60,000 souls; the Buczyna forest, where the Nazis executed more than 800 children; and the Auschwitz-Birkenau concentration and extermination camps.

Polish-born Leon Shear, 91, of Beachwood, Ohio, was one of three Holocaust survivors on the trip. He was accompanied by his son, Howard, and his grandson, Jeremy.

“Listening to Leon’s stories when we visited Auschwitz, it dawned on the members of our mission that he never had a bar mitzvah,” Mr. Steinberg said. “He was liberated at age 14.”

Rabbi Peter Weintraub, FIDF’s national president, wanted to do something special for Mr. Shear, Mr. Steinberg said, but the schedule was too tight to allow for it. “The only time we had would be on the four-and-a-half-hour flight to Israel,” he said.

Before the flight Mr. Steinberg went with Rabbi Weintraub’s wife, Ellen, to browse in the Katowice Airport duty-free shop. He soon sensed that she was trying to get rid of him. “Later I understood she was buying the candies to throw at Leon and she wanted to keep it a secret.”

Little did either of them know that those candies would shower him too.

But first the mission members experienced another highly emotional scene. Before takeoff, El Al Captain Ofer Aloni announced that he had requested to pilot this mission because all four of his grandparents had perished at Auschwitz. The captain then took out a guitar and led the passengers in singing classic Jewish songs. A flight attendant caught the moment on a video that soon went viral in Israel. (To find it, google “Facebook FIDF pilot singing.”)

After takeoff, FIDF National Director Major General (Res.) Meir Klifi-Amir came to Mr. Steinberg’s row to share the news that they had decided to make an impromptu bar mitzvah for Mr. Shear. Everything they needed already was onboard: rabbi and cantor, prayer shawl and Torah scroll. It was a Monday, one of the three days of the week when the Torah is read publicly, so all the conditions were perfect.

“My wife said to General Klifi, ‘You know, Aharon didn’t have a bar mitzvah because the Six-Day War broke out that day,’” Mr. Steinberg said. “So he said, ‘Okay, we’ll do two bar mitzvahs.’”

The general cleared the idea with Rabbi Weintraub, who then tried to make an announcement on the loudspeaker, “but nobody listened because they were still singing and dancing,” Mr. Steinberg recalled.

Finally Rabbi Weintraub got everyone’s attention and invited them to the back of the plane, where an IDF soldier was preparing to chant the day’s Torah portion. For the fourth and final aliyah — the calling up of a member of the minyan to say a blessing over the scroll at set points in the reading — both Mr. Steinberg and Mr. Shear were summoned.

“As soon as we were done, everyone started throwing the candies at us,” Mr. Steinberg said. “We all sang again, and it was a joyous moment.

“Think about it: 30,000 feet above ground is the closest you can be to God unless you’re aboard Gemini or Apollo. What’s the probability that an opportunity like this would come along? You couldn’t duplicate it.

“I will send a letter to Guinness World Records to see if anyone has ever had a bar mitzvah at that altitude.”

More than five decades after the Six-Day War, Mr. Steinberg doesn’t recall how he felt about his “real” bar mitzvah being cancelled. The trauma of the sirens and the shelter, the blackouts and the existential worry during that tense time overpowered his emotions, he explained.

He still has the recording of the Torah portion that his bar mitzvah teacher made for him. As to why the ceremony didn’t take place once the war was over and miraculously won, he only can guess it had something to do with his parents’ earlier trauma of surviving the Holocaust, a period of their lives they never talked about.

Mr. Steinberg and his sister were born in Romania after the war. The family emigrated in 1959 after getting governmental permission, leaving on very short notice, carrying only one small suitcase.

“We spent three months on the road from Bucharest,” Mr. Steinberg said. “In Naples, we waited for the Theodor Herzl vessel to take us to Israel. When we arrived with other new immigrants, we were put in Upper Nazareth and lived there for two years.

“During that time I was lucky enough to be in the filming of ‘Exodus’ along with the other kids in my kindergarten. It’s easy to spot me in the movie; I’m the boy on the shoulders of Paul Newman!”

The family moved several times before settling in Ramat Gan in 1964. After high school and service in the air force, Mr. Steinberg worked for Israel Aircraft Industries; he was on the team that designed the first Israeli drone in 1974. In 1977, he took a two-year leave of absence and came to New York to earn an engineering degree at Brooklyn Polytechnic.

Just before he was to go back to Israel, he met his future wife, Orly, and they decided to remain in the United States. They have lived in Ringwood since 1982 and have three daughters — Monica, Tara, and Jaymee — and two grandchildren. Monica Steinberg is the FIDF development associate for New Jersey.

The Steinbergs have been active in the Solomon Schechter School of Oakland and other Jewish and Israeli organizations, and belong to Chabad Jewish Center of Upper Passaic County.

For the last 33 years, Mr. Steinberg has been in the travel business. It is therefore quite fitting that his belated bar mitzvah was a spontaneous in-flight ceremony as part of a mission symbolizing the journey of the Jewish people from Holocaust to independence.

After landing in Israel, the delegation visited military bases, commemorated Yom Hazikaron — Israel’s Memorial Day for fallen soldiers and victims of terror — and celebrated Israel’s 70th Independence Day. They met with Israeli Prime Minister Benjamin Netanyahu and President Reuven Rivlin.

“This mission comes at a crucial time, and is one of the last opportunities for survivors to return to Auschwitz and tell of its horrors,” Rabbi Weintraub said. “We passed through the gates of hell, ignoring the false promise that ‘work will set you free,’ where countless Jews suffered from unimaginable cold, hunger, and despair. We were surrounded by those who survived within the camps’ walls, and also by those who make sure their stories are not forgotten — the brave soldiers who protect their legacy.”