Currently they land on an autonomous ship (huge flat barge with stationkeeping engines and autonomous control). Reason is, they haven't yet proven that their ap

Currently they land on an autonomous ship (huge flat barge with stationkeeping engines and autonomous control). Reason is, they haven't yet proven that their approach and landing are accurate enough to get permission to try a landing on land. If the rocket misses the ship, it goes for a swim and damages nothing except itself. It it goes out of control during approach over land, there's much more damage it can do to all kinds of things. Also, there's no land downrange from the launch site, and returning the stage to land at the launch site costs a lot of extra fuel. It is possible and actually planned to do so later (SpaceX is constructing a landing pad for this purpose at the Cape at this time), but for now they are trying to get the ship landings down properly.