I would like to fix the errors in the layout of the airport where I am currently earning my pilot license.  The airport is KEHR.  There are 5 hangars you can rent spaces in, 1 privately owned (by our family owned company where we keep our Mojave), and 2 owned by Don Davis Aviation that runs the airport.  I would like to add these buildings as weel as change the textures of them.  I would also like to put a few planes on the ramp and a fuel truck.  The office building is currently under construction as well as the runway when this is finished I'd like to edit those too.  Can anyone tell me what I need to do this and how to do it. 

                                        Thanks,
                                        mojavepilot

The easiest FS9 utility for what you want to do is Rwy12, in my opinion.