I guess the first question is, where do you work and what does it look like? Is this USA?
My first guess is that it's a Harley Davidson WLA. Very common V-twin, but too heavy to be dropped on a parachute in WW II. Airborne used some small 2-stroke singles, I believe, but that's all I know about them. Also Cushman scooters.
Could also be an Indian, if it's a V-twin. Looks a lot like the Harley, with detail differences. Easiest to ID by the tags on the motor & chassis.
Norm Samuelson