A tailless aircraft (often tail-less) has no other horizontal surface besides its main wing. The aerodynamic control and stabilisation functions in both pitch and roll are incorporated into the main wing. A tailless type may still have a conventional vertical fin (vertical stabilizer) and rudder.
Theoretical advantages of the tailless configuration include low parasitic drag as on the Horten_H.IV soaring glider and good stealth characteristics as on the Northrop B-2 Spirit bomber.
The most successful tailless configuration has been the tailless delta, especially for combat aircraft, though the most familiar tailless delta is the Concorde airliner.
NASA has recently used the 'tailless' description for the novel X-36 research aircraft which has a canard foreplane but no vertical fin.