Enemy Ace (Hans von Hammer) first appearance was in DC's Our Army at War #151 (Feb. 1965). He went on to appear in Star Spangled War Stories as a regular feature from #138 to #150. Von Hammer appeared in various DC war titles over the years. He was also the subject of two graphic novels: Enemy Ace: War in Heaven and most notably Enemy Ace: War Idyll by George Pratt.
Originally created by writer Robert Kanigher and artist Joe Kubert, Enemy Ace has also been depicted over the years by artists such as Russ Heath, Neal Adams, Howard Chaykin, and Frank Thorne.
DC Showcase #57, August 1965. Cover art by Joe Kubert.
DC Showcase #58, October 1965. Cover art by Joe Kubert.
Star Spangled War Stories #138, May 1968. Cover art by Joe Kubert.
Detective Comics #404, October 1970. Cover art by Neal Adams.
Enemy Ace sketch by George Pratt, 1991.
Cover art by Frank Thorne for Comic Reader #104, 1974.