We lost more airmen in WWII to accidents of this nature that we did in combat. I think it is on the order of 15,000 just in CONUS non-combat dead from training. Overseas the accidents happened at a similar rate. Then factor in collisions just like this in combat.
In 1940 the accident rate was 50 per 100k flight hours.
Today in the USAF it is around 0.94.
We scarcely fathom the carnage of that war.
Here are two P-40s colliding also.
https://www.youtube.com/watch?v=g7A4MzYxUtc
That's incredible, assuming it's true. But I think an argument can be made that if a group of bombers is under fire and one zigs in the confusion while another zags, or if an escorting fighter is avoiding a pursuer and strikes a bomber, those losses should be counted as combat losses and not aviation "accidents".