Jean Caillet still remembers being a 20-year-old air force mechanic in Britain during World War II and hearing Allied forces had landed on the beaches of German-occupied France.

"We were happy, of course. We were perhaps going to see our country again," the heavily decorated 100-year-old Frenchman of Jewish heritage told AFP.

Caillet was one of millions who worked behind the scenes of the Normandy landings on June 6, 1944 that paved the way towards expelling Nazi forces from France.

That summer he was part of just two French Air Force heavy bomber squadrons -- dubbed Guyenne and Tunisie -- that contributed to the Allied aerial campaign in France from behind the lines at a Royal Air Force base in Britain.

In the British village of Elvington, 11 kilometres (seven miles) southeast of York, Caillet and his colleagues had their work cut out for them.

"When you're 20, it's an adventure," he said, eyes sparkling.

"I was a ground mechanic," he added, explaining he was in charge of checking the fuel gauge, speedometer and altimetre on the heavy bombers before they took off.

"Sometimes it took five minutes, others an hour. I would check five to 20 planes a day. Almost all of them took part in the Normandy battle," he said, adding he was "proud" to have played a role.

- 'Hungry during the war' -

In Elvington, he recounted, he made life-long friendships, as well as discovered pints of beer, whisky and the charms of young women.

But war-time rationing and bomb-scarred cityscapes were a reminder that a conflict was on, especially when he travelled to London on leave.

"Missile shrapnel would rain down in the street," he said.

As friends took off across the Channel, Caillet -- who was not religious -- would sometimes wish them "merde", the French version of "break a leg".

But one out of two pilots in the Guyenne and Tunisie squadrons never made it back to base.

Caillet said he would have liked to fly a plane too despite the risks.

"But I didn't have the build," he said.

"Being hungry during the war must have been a factor... There wasn't a lot to eat in France and Spain.

- Spain, Morocco, Algeria -

Caillet was born in the northern French city in Amiens on November 8, 1923.

He, his parents and little sister spent the first years of World War II there, then fled bombardment to the tiny Normandy village of Mortemer.

Living conditions were tough under German occupation, and in early 1942 he decided to flee to escape being rounded up.

He found refuge with an uncle across the line in Free France, then decided to leave to join the Free French Army fighting German forces in North Africa.

He managed to cross the southern border into Spain, but he was arrested for being undocumented and jailed in the northern city of Girona.

After the Red Cross intervened to have him released, he caught a train to Portugal, then found a spot in the tick-infected hold of a former livestock ship heading to North Africa.

He docked in Morocco in June 1943, signing up to join the air force, hoping initially to be a pilot.

He said he had "terrible memories" of the heat in Morocco, and then caught malaria in next-door Algeria.

By late 1943, he had docked in Liverpool to join the RAF.

But he was worried about his family after learning his Jewish mother and sister had been arrested.

- Return home -

He returned home after the war ended, finding his home had been plundered after being occupied by German forces and no sign of his family.

"I never found my father, mother and sister. I never heard from them again," he said.

Caillet married and settled in the Normandy fishing port town of Dieppe, where he still lives to this day on a street named after him.

He and his wife, who opened a shop after the war and had three children, between them had lost 15 relatives in the conflict.

Only years later in 1978, through the work of Nazi hunters Beate and Serge Klarsfeld, did Caillet discover what had happened to his family.

His father was arrested in August 1942, while his mother and then 15-year-old sister were detained the next year. They were deported to an extermination camp in Poland.

© Agence France-Presse