A Hot air balloon is seen at the Cup Hot Air event during the Air Sports festival titled “70 Years of Peaceful Sky” in Minsk, Belarus July 18, 2015. (Photo by Vasily Fedosenko/Reuters)

Spanish Patrulla Aguila (C-101), aerobatic demonstration team of the Spanish Air Force performs during the Radom Air Show at an airport in Radom, Poland August 23, 2015. (Photo by Kacper Pempel/Reuters)

The Screamin' Sasquatch jet powered Waco Biplane sits on display during media day for the Canadian International Air Show at Billy Bishop Airport, Toronto, Ontario, September 4, 2015. (Photo by Louis Nastro/Reuters)

An injured girl reacts at a site hit by an airstrike in the rebel-held Douma neighbourhood of Damascus, Syria November 7, 2016. (Photo by Bassam Khabieh/Reuters)

A Russian air force technician reports to a pilot that a bomber is ready for a combat mission at Hemeimeem air base in Syria Wednesday January 20, 2016. Russian warplanes have flown over 5,700 combat missions since Moscow launched its air campaign in Syria on September 30, 2015. (Photo by Vladimir Isachenkov/AP Photo)

In this photo taken Thursday, May 7, 2015 photo, remains of Soviet soldiers killed during World War II lay in a coffin prior to a reburial ceremony at the Sinyavino Heights memorial near the village of Sinyavino, 50 km (31 miles) east of St. Petersburg, Russia. Hundreds of people came to a World War II battleground outside St. Petersburg this week to bury the remains of 964 Soviet soldiers recovered by volunteer search teams. Fifty crimson coffins containing skulls and bones were solemnly buried at the Sinyavino Heights memorial as Russian war songs played and an honor guard fired a salute. (Photo by Dmitry Lovetsky/AP Photo)

The War in Abkhazia from 1992 to 1993 was fought between Georgian government forces for the most part, and Abkhaz separatist forces, Russian armed forces and North Caucasian militants. Ethnic Georgians who lived in Abkhazia fought largely on the side of Georgian government forces. Ethnic Armenians and Russians within Abkhazia's population largely supported the Abkhazians, and many fought on their side. The separatists received support from thousands of North Caucasus and Cossack militants and from the Russian Federation forces stationed in and near Abkhazia. Here: Abkhazia. Sukhumi, 1993. A house-to-house combat. (Photo by Andrei Solovyov/ITAR-TASS)

Pilots plan a flight manoeuvre with model aircraft at a military air base in Vasylkiv, Ukraine, August 3, 2016. (Photo by Gleb Garanich/Reuters)