Spectators take pictures during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)

A spectator takes pictures during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)

A boy plays with a model of an airplane during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)

A boy holds a model of an airplane while watching an air demonstration during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)

Single-engine airplanes fly in formation during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)

People watch an air demonstration during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)

A single-engine airplane makes maneuvers during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)

Single-engine airplanes fly in formation during the Athens Flying Week at Tanagra air base, north of Athens, Greece, on Sept. 22, 2018. (Xinhua/Marios Lolos)