There's a tag for museum aircraft, 'historic=aircraft', but the tiles rendered for openstreetmap.org don't show it, so people add a tag saying it's also a building.
It's only a theory, I haven't correlated a picture from the game with matching data.
If I had to guess it's an AI going wild on some kind of military (swept wings?) airfield - they looks like plane's but I'm assuming the AI system they use assumes everything not terrain is a house or a road or similar.
