Offline traffic (fs9,fsx, p3d and MSFS) is defined by files in the form of “traffic_some airline air.bgl”. In my setup MSFS default offline traffic is here:
To decompile traffic files you need some program. In this case I decompile default traffic with AIFP3 which is available here:
Stuff 4FS - AI Flight Planner
In the picture attached you can see the interface.
AIFP is a very handy program if you want to compile/create/modify traffic files. I’ve been doing that for almost 15 years. If you want to experiment you will find lots of files at avsim, aig, flightsim.com.
Boat traffic now is different somehow and requires a different program. You can find one in this site with useful information:
Flight Simulator Ships Project (gratisim.fr)
I have never used it, so I can’t be more informative but I think it is what you need. It is possible that you will need fsx sdk but I am not very sure. In any case, if you need it I think you can find fsx sp2 sdk (previous fsx sdk are discontinued, so I am not sure if it will work) here :
SDK Installation (FSX) - FSDeveloper Wiki