In spite of occasional crashes, such as the loss of Britain's only flying Mosquito fighter-bomber on Sunday, a powerful lobby believes that historic aircraft belong in the air. The difference, they say, is between stuffed animals in a museum, and living animals in a zoo.
"There are several thousand of these aeroplanes worldwide, most of them in the US," said Stephen Grey, head of the Fighter Collection based at the Imperial War Museum at Duxford, Cambridgeshire. "Ten years ago there were three or four Spitfires flying in the world: now there are 25. There were about 40 Mustangs - now there are 100. Fifteen years ago there was one Lancaster: now there are two, and others are under restoration."
The loving care lavished on historic aircraft is not limited to Allied planes. A decade ago, of the 22,000 German Me-109 fighters built, none were flying. Now, Mr Grey said, three or four are flying and a similar number are being restored.
The privately sponsored Fighter Collection, with 18 flying aircraft and 13 undergoing restoration, is only one of many in Europe. The RAF's Battle Of Britain Memorial Flight, whose aircraft take part in official fly-pasts, has one Hurricane and another being restored, a Lanc- aster, and five Spitfires. The Navy retains its own Historic Flight, with a Sea Fury, a Firefly and two Swordfish.
More effort is now put into restoring the aircraft than would have been expended on them in wartime, when they were built. Engine and propeller parts can be taken from aircraft too damaged to restore. Other parts - wooden and aluminium spars, structural parts and rivets - are made from scratch.
When an old aeroplane crashes, it is usually through "human error". The aircraft, designed for war, were usually pushed to the limit in their development; large numbers were expected to be shot down, and safety was not a priority.
"They're big gyroscopes, essentially, with an enormous propeller on the front," said Mr Grey. "If something goes wrong it's a question of knowing what to do." He refused to speculate on the cause of Sunday's accident. But in previous cases, he said, pilots had been distracted, or had made simple errors.
The determination to keep historic aircraft flying stems from the belief that there is more to history than the mere artefact.
"It's not a glorification of war," said Mr Grey. "The jet has obviously been an amazing technological change. Piston-engine technology has reached its end. That's a reason for maintaining it. Historically it's pretty important to see these things in their prime element, which is in the air. How would a child know what a Spitfire is, if he just saw it in a museum?"
Restored to flight
Piston-engined military aircraft flying, worldwide
Spitfire 3-4 25
Lancaster 1 2
Mosquito 0 2-3
Beaufighter 0 1
Mustang 40 100
Fortress N/A 10
Me-109 0 3-4