Star Spangled War Stories #147 (On Sale: August 19, 1969) has an Enemy Ace cover by Joe Kubert.
"A Grave in the Sky" is by Robert Kanigher and Joe Kubert and, my god, is Kubert on fire this issue. The story surrounds a British pilot who as a child was obsessed with the story of St. George and the Dragon. Years later he is still obsessed and sees the RAF as a way of attaining knighthood and flying a steed and using machine guns as his lance.
The delusional pilot wears the top half of a suit of armor when he flies and believes himself to be the reincarnation of St. George. As with all Enemy Ace stories, the real story is about the killer skies and the terrible strain leading men into battle is for Hans Von Hammer. It has some amazing Kubert artwork, bringing the aerial dogfights of Fokkers vs. Sopwith Camels to glorious life. Kubert in his early 40s at this time was a master of the brush for sure, but it is his amazing story-telling abilities that make these books come to life.
Suffice to say that in the end St. George is defeated by his own personal dragon, Hans von Hammer, the Enemy Ace. This story was reprinted in Enemy Ace Archives Vol. 2 HC and Showcase Presents: Enemy Ace Vol. 1 TPB.
Edited by Joe Kubert.