MiG-15 jet fighters are pictured in Kucova Air Base in Kucova, Albania on October 3, 2018. Albania retired its 224 Soviet- and Chinese-made MiGs in 2005, and since 2009 NATO neighbors Italy and Greece monitor its airspace. That led to economic decline in and around Kucova, which was called “Stalin City” during the era of Communist rule. (Photo by Florion Goga/Reuters)

A Russian ground staff member signals to the pilot of a Sukhoi Su-25 fighter jet at the Hmeymim air base near Latakia, Syria, in this handout photograph released by Russia's Defence Ministry October 22, 2015. (Photo by Reuters/Ministry of Defence of the Russian Federation)

A red fox sits in front of a Eurofighter Typhoon combat jet on the grounds of the 2014 ILA Berlin Air Show, in Selchow near Schoenefeld, Germany, Thursday, May 15, 2014. The International Aviation and Aerospace Exhibition ILA will take place from May 20 until May 25, 2014. (Photo by Patrick Pleul/AP Photo/DPA)

This plane looks like it's bound for the moon as it shoots across the sky. Photographer Sebastien Lebrigand was impressed he could even see the lights on the jet's wings in this stunning silhouette. (Photo by Sebastien Lebrigand/Solent News)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

A World War II era P-51 Mustang fighter plane stands in front of a modern 747-8 freighter and a 757 passenger jet at The Boeing Company's centennial celebration in Renton, Washington, U.S. July 15, 2016. (Photo by Alwyn Scott/Reuters)

Sukhoi Su-30SM jet fighters of the Sokoly Rossii (Falcons of Russia) aerobatic team fly in formation during the International Army Games 2016, in Dubrovichi outside Ryazan, Russia, August 5, 2016. (Photo by Maxim Shemetov/Reuters)

The homemade Airbus A320 jet plane made by Chinese farmer Zhu Yue is being built at an open space in Kaiyuan city, northeast China's Liaoning province on February 4, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)