An unpowered aircraft that flies by riding air currents. The term グライダー is more common in everyday Japanese.
See also: グライダー
A glider was silently soaring through the sky.
Compound of 滑空 (kakkū, 'gliding') + 機 (ki, 'machine'). The exact historical derivation is uncertain, but the kanji straightforwardly describe a gliding aircraft.