The online retailer is trying to figure out the best way to actually leave the package at the intended destination. Landing the drone runs the risk of injuring bystanders. Nobody wants a drone to land on their dog. And if somebody nearby has questionable ethics, then hey, free drone.
So Amazon is considering releasing the package from the air, or as the patent states, they're looking for a mechanism to "forcefully propel a package" from the drone. The question then becomes how to do so accurately and without harm to the package (or that theoretical dog I mentioned earlier). The three methods being discussed are, in order of insanity: a parachute, landing flaps, and compressed air canisters. Parachutes and landing flaps are still susceptible to high winds, so the compressed air canisters would correct course and assure that the package lands where it's supposed to.
I can't imagine any of this would be remotely cost-effective. However, this is all very preliminary, so hopefully Amazon can figure out a method that doesn't turn my Blu-Rays into dangerous projectiles.