HT built the Aces High graphics engine from the ground up. End of story. They have a bit of similarities mainly because HT was the main man behind Warbirds too. Don't forget that Natedog, Pyro, Ronni, Yankee and myself all worked for iMagic and on Warbirds together for a number of years. My drawing style hasn't changed too much since then, although I hope it's improved some, which is another reason for things looking similar.