Home / United States / World War II / Posters / 1951 Dated Poster: “Keep ‘Em Flying! U.S. Air Force” SOLD! 1951 Dated Poster: “Keep ‘Em Flying! U.S. Air Force”$275.00 Approximately 16-7/8 inches by 25 Inches. The poster was never folded and it is in excellent condition. Sold! Item Number: 60863 Category: Posters