Glad to see you're making progress.
If you put a floor in your hangar, texture it, then set it on the ground you get texture flickering because FSX gets confused as to whether it should display the floor or the ground underneath it.
You can raise the floor a tiny bit in Sketchup or you can raise the entire hangar a bit above ground level in FSX. Either way will eliminate the flickering, yet give your plane a "flat tire" look should you park in the hangar. Your personal opinion which is best.
Personally I would rather create the floor with an apron in ADE and sometimes when using hangars created by others will sink them into the ground a bit to bury their floor.
Using an apron eliminates the floor polys, and their textures, which makes the model perform better in the sim.
Keep up the good work, and most importantly, have fun.
WWOD---What Would Opa Do?
Farewell, my freind (sp)