Additional info: you might want to give it (the structure) the tag Insignificant=yes, so that you won't hear the "unit lost" sound when it gets blown apart. At least I think that's the right tag for this...
Also it doesn't have to be a chopper, it can be a normal vehicle or a hovercraft type of vehicle. You can give it the tag Immune=yes if you like to make the chopper totally invincible (but obviously not the aid package). This ensures that your little gift package will be very safe in reaching your ally, since you might usually want to send the package as fast as possible without fear of it crashing. In that case you can give it high speed and turning speed as well. Or you could go totally "top secret" - make it stealth and invisible to radar. This further prevents enemies (or other allys) from discovering that you are giving something to a friend, so you can make safe and secure transactions
The Soviets will have an advantage with this unit once they build an Industrial Plant. They will be able to make money by building many of these Choppers, deploying them, destroying the aid package, and collecting the crate. But you can either accept this as a slight advantage that the Soviets have, or you can make hte build time of the choppers long enough to deter the player from mass-producing them.
Of course, this whole thing won't be much use against a comp. player, unless you feel sorry for it's terrible AI (I do)