I have come across this sort of subterfuge twice in my career.
The first incident was quickly sorted out. The person concerned was claiming seniority and promotion based upon his flying time in the RAF. Sadly for him, the 5,000 hours or so that he was claiming was not earned while sitting in a seat that had a window view.
The second one was a real Walter Mitty character who ended up as an LTC on the DC-10. He would regale us all down the route (especially the girls) with stories of how he ferried Hunters to the Far East in the RAF which must have been a particularly clever trick since he had never been a pilot in the RAF.
The interesting thing is that he would continue to recite these yarns even after I (and many others) had pointed out the above to him.
I am sure that it is a total coincidence but both of them had been navigators.