I keep sending my folks back to base after every single mission since they apparently scrub the decks while flying, anyone who has been a soldier knows that a bed is a luxury left to the imagination at times.
You lose 1 stamina per turn and up to 10 in a single mission. Anyone knows when they are tired and fatigued? … the exact numbers.
When they have <=10, you lose 1 AP. I forgot this number myself, and tried to find it in the Phoenixpedia… there was NOTHING on stamina in it.
So, you can basically keep doing missions non stop, until they hit 10 stamina. Presumably, even if you recover just 1 point of stamina above 10, you can then do missions unpenalized, if there is a sudden haven attack or such? Good way to exploit that, I figure.