Everything made in GIMP and Mypaint, using both mouse and a Wacom Bamboo Manga with pen. The windows of the larger buildings in the cityscape are textures that I pre-made separately; I've used them before. The windows on the smaller buildings are just maxed-out HSV noise done a couple of times, with gauss blurring and cartoon filters in GIMP. Everything else is digital speedpainting with jwarping, several layers. Aircraft were done separately, added after the cityscape.