Not that you can tell it by looking at my portly figure now days, but I used to do a lot of backpacking. I use an old nylon strap with a plastic buckle that was for strapping tents and sleeping bags to my pack. It is very easy to unclip with one hand while holding the air plane or transmitter. It also is adjustable in length so I can attach it to a fence post, starting stand or whatever is around.

http://www.campmor.com/outdoor/gear/Product___48054

You could probably find something very similar at a local sporting goods store or even walmart.