out of curiosity
I wonder if a remote-controlled twelve-foot helium blimp could successfully fly across the Atlantic? The control system would have to be wireless, obviously — maybe pull the guts out of a high-quality PDA, or maybe a cell phone, and replace the blimp's receiver. (A cell-phone control would kill you on roaming charges, though.) There would be a serious problem with power, though — most of these remote control systems have a maximum battery life of two hours.
Maybe a remote control glider would be a better idea?