The below video purported to depict the "Ghost of Kyiv" ace fighter pilot shooting down a Russian jet is actually footage from a 2013 videogame called Digital Combat Simulator: World. If only all this very real horror was a videogame. From Kotaku:
Developed by Eagle Dynamics, a company founded in Russia but which is now headquartered in Switzderland, DCS: World's default map is set in the Caucasus region near Russia, Georgia, and Crimea.
A spokesperson for Eagle Dynamics, Matthias Techmanski, confirmed to Reuters that the fictional video from YouTube spreading like wildfire on social media was indeed from DCS. "We are not responsible for its distribution, nor do we endorse such content," he said.