Scale Model Accessories (website link in my profile) will be releasing 1/72 USAAF/USAF ground crew and a few vehicles and trolleys before the end of the year (I've just completed the pattern for the Clark Clarktor), but that might be late for you...
Hasegawa has a 1/72 US fuel truck. And a cargo one too. They have the Jeep, but so have Fujimi (1/76), Matchbox (1/76), ESCI (1/72), Italeri (ex-ESCI)... Airfix used to have a box of USAAF ground crew but it's that soft plastic that's so hard to clean up properly...