Hello!
First off, welcome to the SimScale forum!
Generally, I’d ask for more details to help you out, but I think a good starting place for a very similar case is to just follow along the following Aerodynamics tutorial for an aircraft wing: Compressible Flow Around a Wing | Tutorial | SimScale
It seems like you’re working with the Incompressible Analysis Type, which means the only part of the geometry you want present to the simulation setup is the Flow Region, and not the solid bodies of the aircraft itself. The tutorial above begins with how to prepare your geometry for a aerodynamic flow simulation. Since this kind of CFD simulation only simulates the flow around the body, the CAD body/geometry should represent the air volume you’re simulating, with a ‘cutout’ where the solid bodies are.
Feel free to reply here with an update if the tutorial and note above got you going in the right direction or if you need further assistance.
Cheers,
Omar