The U.S. Navy wants to buy a long range maritime reconnaissance UAV. This aircraft might end up replacing the current fleet of P-3 aircraft. To gain some experience with this sort of thing, the navy is buying two Global Hawk long range UAVs. This aircraft can stay in the air 36 hours and travel 24,000 kilometers in a single sortie. The Global Hawk has already crossed the Atlantic and Pacific oceans on its own (using software to control it, not a pilot on the ground.) While some thought was given to building a naval reconnaissance UAV that could operate from a carrier, it's been decided to go for the larger UAVs so that more sensors, and perhaps weapons, can be carried. The navy has long operated it's fleet of P-3s from land bases and that has never presented insurmountable problems. Smaller UAVs are being developed that can operate from carriers. Sending up UAVs, instead of manned maritime patrol aircraft, is a lot cheaper. This is because flight crews require special training and flight pay. Even at that, serving in maritime patrol aircraft is not very popular duty. It can be boring, and there is some danger. Operating the UAV from the ground is also a lot safer for the crew and it allows the local commander to send a patrol UAV into a dangerous situation without risking a crew. Moreover, the longer sortie time of the Global Hawk has proved to be a major advantage, allowing the UAV to scan below until the enemy made their move. A maritime patrol UAV could do the same thing when hunting submarines, or anything else down there.