People visit an "Osprey" during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 9, 2018. (Photos: Xinhua)

A Czech Air Force Gripen performs during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 8, 2018.

A glider performs during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 9, 2018.

A Dutch Air Force KDC10 tanker and F16 fighters fly above the Kleine Brogel Air Base during the Belgian Air Force Day in Belgium, on Sept. 8, 2018.

Aerobatic team "Patrouille de France" perform during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 9, 2018.

Aerobatic team "Patrouille de France" perform during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 9, 2018.

A Belgian Air Force F16 fighter and a vintage Spitfire perform during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 9, 2018.

A SeaKing helicopter performs during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 9, 2018.

British paratroopers perform during the Belgian Air Force Day in Kleine Brogel Air Base in Belgium, on Sept. 9, 2018.