WW II submariners had the highest death rate per capita of ANY branch/division of ANY of the military services.
Some bomber crews would like to have a word with you
https://www.iwm.org.uk/history/life-and-death-in-bomber-command
Only because the 8th Air Force (in the European theater) kept increasing the numbers of air crewmen they were sending to Europe once the Allies had air supremacy and there was little threat to American air crews. Which dramatically decreased their overall casualty rate.
But in the early campaigns, their losses were staggering. They lost 60 -- SIXTY -- B-17s in one mission alone, the August 17, 1943 raid on Schweinfurt (with roughly the same number badly damaged). In large part because they (mistakenly & misguidedly) believed the B-17's 13 M2 50-cal machine guns made them invulnerable to fighter attack, so the US committed to daylight missions and left the nighttime raids to the Brits.
Overall the 8th Air Force lost several times more aircraft than the Pacific submarine fleet did submariners.