This is just a modified wind-up toy, so the potential for real interaction is lower than with a lot of other toys. Essentially all one can do is wind it up and let it fly.
Principles
The dominant principle this toy works with is air resistance, and the fun of playing with is entirely reliant on how interesting the user finds parachutes. I think most children will inevitably have it jump off of higher and higher surfaces, so there can be some lessons about air currents in there too. There is stored energy in the jumping foot spring, which while necessary to the toy's function, is not the focus. Additionally, if a child thought about the toy (like our second class), he or she could learn a little about backwards engineering and possibly gears.
Feasability
This toy would not be more expensive than your average wind up toy. Die-casting different parts should not be more expensive, and the only additional manufacturing/material costs would come the parachute. I do not know what it costs to attach a small toy parachute to the inside of a small toy truck, but I don't think it will be a considerable amount.
Like many wind up toys, this one will not be extremely durable. The parachute strings are liable to break, and the entire point of the toy is to drop it off of something very high up. If the parachute fails, the structure will probably fail on impact.
The paratrucker ranks relatively low on the safety scale. The (probably) plastic parachute is a choking hazard, and so are a few of the small pieces of the toy should it break. The spring loaded jumping foot could possibly hurt someone, and when locking everything back together for a second run there is a possibility of pinching a finger. As long as the age range is set sufficiently high, I don't think many people could injure themselves too severely with it. Though if you put the back end of the truck in your mouth and were chewing on it, and the locking pin fell out, you would get kicked in the mouth and have a parachute drop down your throat, which would be unpleasant at best. I think the age at which it becomes unlikely for someone to do this without knowing full well what they are doing is around 8 or 9, and would set that as the minimum recommended age.
