I thought the USAAF disappeared in 1947 when the USAF came into being.
Correct. I neglected to mention and elaborate on that point. However, it was still the same Air Force - just a bit of re-organisation that freed it from being under the total control of the U.S. Army.
I still feel that these losses are completely unacceptable. I understand that some losses in parachuting must be inevitable - but the fact remains that if the apparently sizeable percentage of vehicles lost in this drop happened in a real-war scenario, it could mean lives lost on the ground.