A Sunday afternoon spent burning money in the form of rocket motors with my son has left me also wondering where that weighted rope went, the one I use for fetching kites / airplanes / frisbees / pets out of trees, off of roofs, and whatnot.
The rocket, true to its nature, went higher than anything
we've ever thrown into a tree by accident, and much higher than I can throw a weight with a line attached.
But I also have a couple of pneumatic potato cannons. These can throw a weight - string attached or otherwise - pretty darned far. And since I can hold it steady, the accuracy is much greater than my usual not-an-athlete throwing can provide.
So we combine the two: the cannon will hurl the weight with the line attached, probably somewhere pretty close to exactly where the rocket is snagged in the tree.
The ideal weight would be shaped like a slim football, tapered on both ends so it will shoot past small intervening twigs. Perhaps a strong rare-earth magnet connection to the rope would be a good idea: if it becomes hopelessly entangled, a very strong tug parts the rope from the weight and the rope can be pulled free while the weight simply tumbles to the ground.
As an individual product, this would probably be best sold in the aisle right next to the little balsa rubber-powered planes and the big styro gliders.