To provide an unmanned aircraft system capable of taking off or landing in a state that an unmanned aircraft and a manned aircraft are combined, the unmanned aircraft used for the unmanned aircraft system, the manned aircraft used for the unmanned aircraft system, and an operation method of the unmanned aircraft system.

The unmanned aircraft system has the manned aircraft 100 and the unmanned aircraft 200. The manned aircraft 100 is provided with a manned aircraft main wing 120, a manned aircraft fuselage 110, a manned aircraft landing system, and a manned aircraft combining mechanism 180 provided at a bottom 111 of the manned aircraft fuselage 110. The unmanned aircraft 200 is provided with an unmanned aircraft main wing 220, an unmanned aircraft fuselage 210, an unmanned landing system 270, and an unmanned aircraft combining mechanism 280 provided at a ceiling 211 of the unmanned aircraft fuselage 210. The manned aircraft combining mechanism 180 and the unmanned aircraft combining mechanism 280 are separably combined.