The phrase "water landing" is also used as a euphemism for crash-landing into water in an aircraft not designed for the purpose. An intentional water landing during distress, but under controlled flight, is called ditching. Such water landings are somewhat common for small craft in general aviation and the military, but they are extremely rare for commercial passenger airlines.

By Design

Seaplanes, flying boats, and amphibious aircraft are designed to take off and land on water. Landing can be supported by a hull-shaped fuselage and/or pontoons. The availability of a long effective runway was historically important on lifting size restrictions on aircraft, and their freedom from constructed strips remains useful for transportation to lakes and other remote areas. The ability to loiter on water is also important for marine rescue operations and fire fighting. One disadvantage of water landing is that it is dangerous in the presence of waves. Furthermore, the necessary equipment compromises the craft's aerodynamic efficiency and speed.

Early manned spacecraft launched by the United States were designed to land in water by the splashdown method. The craft would parachute into the water, which acted as a cushion to bring the craft to a stop; the impacts were violent but survivable. Landing over water rather than land made braking rockets unnecessary, but its disadvantages included difficult retrieval and the danger of drowning. The modern Space Shuttle lands on a runway instead.

In distress

Although extremely uncommon in commercial passenger travel, small aircraft ditchings are common occurrences. According to the United States Coast Guard, including helicopters and fixed-wing aircraft, between military, air carrier, corporate, and general aviation, there is one ditching every day in U.S. waters alone.