According to the manual there are three different pools to get pilots from, trained (c.50 exp), trainee (very low exp) and reserve (high exp disbanded from airgroups for various reasons).
When I click "Get Pilot" is there any way of determining which pool it will be drawn from? The last thing I want is 20 exp pilots going into KB airgroups!
Like Sardaukar said, here is the priority list (with one addition):
1. Existing pilots in Reserve pilot pool that are assigned to the squadron you want to be replaced, available at the time of your call (not WIA and their date of arrival passed)
2. General reserve pilots from Reserve pilot pool, for fighter squadrons all those having Fighter reserve in squadron field.
3. Pilots from Replacement pilot pool with average experience of 35 (in my experience it was +/-6 points, so they can be 29-41 exp)
4. Pilots from different reserve in Reserve pilot pool, taking experience penalty (bomber reserves pulled into fighter squadrons for example)
5. Cadets with unfinished training with experience below 30. If both your pools are empty these will be drawn, and the more you draw them the less experience they'll have. But for quite a long time you won't see these, and by the time you see them you will know everything about the game
Note that there are two pools in the game, Reserve pool and Replacement pool. People usually confuse them,
Reserve pool has named pilots that are already generated in the game, with existing experience and skills. This includes both historical pilots and the ones generated after the game start.
Replacement pool is just a random number generator, generating new pilots around experience specified for the nation and service (so for IJN it is 35)