In addition to KIA and wounded, they are probably counting POW’s in the “losses.” The Marines didn’t have many POW’s in the Pacific. But if you figure the average number of planes on a mission, the number of crew per plane, and the percentage of aircraft lost per mission, over time it adds up. Not to mention the killed and wounded on the planes that made it back to England.
Per The Mighty Eighth Air Force museum: The 8th AF suffered one-half of the U.S. Army Air Forces’ casualties in World War II (47,000-plus casualties with more than 26,000 deaths). The Eighth’s personnel also earned 17 Medals of Honor, 220 Distinguished Service Crosses, 850 Silver Stars, 7,000 Purple Hearts 46,000 Air Medals.