Can someone explain how crew training works? I have a Tundra Training Akademy in orbit around Kerbin with a level 2 pilot and a level 1 pilot inside. Clicking "Level Up Crew" doesn't do anything and says "No astronauts on board are ready to gain experience."
Edit: nvm, found the "Conduct Training" button, which does what I want. This leaves me confused as to what "Level Up Crew" does.