Closely related: Do ships sink nowadays?
The first powered, heavier-than-air airplane flight was in 1903. The first death in an airplane crash occurred in 1908. Therefore for the first five years of the airplane, there were zero deaths per passenger mile in air travel. By this metric, air travel was as safe or safer than sea travel.
It’s my belief that air travel today also has fewer deaths per passenger mile than sea travel (but I could be wrong!).
Looking at deaths per passenger mile, has air travel always been safer than sea travel? If not, during what period(s) was sea travel safer?