A problem or flaw with this story which always botherd me.......

I have always loved this film, and it is in my top 5 of all time.
However, there is a plot flaw that is not addressed in the film, and certainly not the book the screenplay was derived from.

The set up of Pierre having amnesia and vertigo, being somewhat nursed back to heath (to a degree) by his now girlfriend which is the root of his psychological problems perplexes me.

HOW can he not know who he is?

He was a fighter pilot in the French air force. He must have had many means of identification on him. Dog tags, the number on the plane, personal items in his pockets?

Even if we assume he was held prisoner for a time after being shot down, and even if the plane was totally destroyed, he still could be identified by fingerprints!! Not only that, but he could be compared to photographs of airmen lost in battle or MIA.
Don't you think the military has copies of fingerprints of EVERY member of armed forces???

The French military like any other can ID bodies that have been dead and decomposing, so how can they not ID a living person. Wasn't his family looking for him? He was only in his early 30's. Surely he had some relatives etc.

This flaw always troubled me, as it is the crux of the plot. I am sure this could have been dealt with in the screenplay which for the most part was totally original, the relationship between Pierre and Cybele being only a very small part of the novel.