In looking at some of the replies, I've noticed that some people have concerns over the BIS or IAB conflict, that only one can the be -the- bretonian intelligence department and people will inevitably be forced to choose between the two. I don't see this being the case at all. The IAB and BIS are both developed and, I believe, will continue to develop into very seperate organizations with both having an individual niche.
The IAB will be the overarching intelligence aperatus of Bretonia, intel is what we do. We go places, find things, and tell those who need to know about what we discovered. Please note that for the most part we are a group of spies, not an assault battalion. That being said, sirius is a big place, and we will not always have the manpower or the expertise the BAF needs to aquire real-time actionable intel. The BIS is perfect for this job. They are a group of well trained pilots who can very rapidly deploy to an area and scout around or conduct precision strikes for the armed forces without the waiting and bureacratic hassel of getting a spy ring in position. thus, each has their advantages and disadvantages: the IAB takes a little longer, but can provide a better quality intel supply, and the BIS is faster, but lacks the resources for a full intelligence operation.
There are several analouges for this system in the real world, with militaries units often maintaing a small group of intelligence staff to provide real-time support in the field. An easy in-game analouge would be the LSF and Gold Wing, both of which have not only survived each other's existence but have thrived in their respective fields.