Complaints below my answer to Would a higher air pressure on the ISS or elsewhere make it easier to “swim” in microgravity? about my spherical-cow estimate of how fast an astronaut can accelerate by "swimming" in air and how that scales with the density of the atmosphere (in ) include terms like "body drag", "frictional drag" and "pressure drag".
I suspect the main reason my estimate was high is that I assumed the velocity of the backwards underhand motion of the astronaut was half of the world's record for the speed of a thrown ball. I should have done some frame-by-frame photogrammetry of the YouTube video instead.
Question: What is the difference between "body drag", "frictional drag" and "pressure drag" in the context of astronaut or aerobot atmospheric locomotion in microgravity?
These concepts will certainly become more important as reduced-gravity-sports evolve over time, as well as crewed missions take place in extended missions in larger spacecraft (e.g. Mars migrations), and in designing small robotic devices that fly around in microgravity environments.