If you are familiar with firearms, you know that there is a part that has a serial number. That part is normally the "frame" or the "receiver". You can replace every other part and it is still, by law, the same weapon. You may go to a match and see a tricked-out .45 race gun that started life as an off-the-shelf Government Model, but by law, it's still the same gun.
With airplanes, the "this is the airplane" part is the data plate. It is normally a piece of sheet metal, stamped with the maker's information. This is one from a Lockheed Vega.
You may, on occasion, have gone to an air show and seen airplanes from the early days of aviation. There, you might have sen a 1923 This or a 1934 That. It might be touted as a "restored original". What you probably don't know is the original parts may be a very small percentage of the airplane you saw and it is possible that the only original part was the data plate.
This is no shit:
Back in the 1950s and 1960s, flying naval aviation jets was a far more hazardous line of work than it is today. It was not unheard of for an fighter jet squadron to deploy for six months on a carrier and suffer a 20-25% attrition rate. In plain English, that meant that a quarter of the squadron's pilots were either seriously injured or killed. And this, mind you, was in peacetime.
Which meant that the Navy needed to buy lots of replacement airplanes. But money for replacement airplanes was difficult to come by; especially during the time that the spending on the Strategic Air Command consumed two-thirds of the military budget. Congress closely scrutinized the amount of money spent on new airplanes.
But Congress paid less attention to the repair budgets. So what some bright soul thought of was to take the data plates from the wrecked airplanes and send them to the manufacturers for "depot-level repairs".
Which meant that the manufacturers would build a new airplane on their production line, affix the old data plate to the new airplane and Voilà! The old airplane was "repaired" and returned to service.
It’s a fair question
15 hours ago