I'm fine with the amount of aircraft I've seen thus far. The Japanese were quite air-centric. It seems some of you are having an unnatural amount of them when anywhere near a Japanese carrier group. I will recommend copying & pasting the config file you modify to a different location in case you want to go back to default later.
However, if any of you want to lower the chance of aircraft showing up, here's what you do:
Go to c:/Program Files/Ubisoft/Silent Hunter Wolves of the Pacific/Data/Cfg/AirStrike.cfg
(or whatever hard drive it's installed on besides the default c
Here you can modify maximum aircraft range, etc. The most useful setting to modify is:
Default Air Strike Probability=10
*This is the default % chance of getting an air attack. Change it to what you desire percentage-wise.
The rest are modifiers for various circumstances such as during nighttime. You can also change the interval check, spacing the check out. The Config file is quite self explanatory - it has notes for each setting.
Mod'ing this file in SH3 worked great, so it should be the same here.