Originally posted by aldo_14
Hmmm.... in all honesty, I prefer custom cockpit maps
Like I would bother making custom maps for something that will never take more than 100*100 pixels on screen

raa:
first, top bar -> customise -> units setup.
Pick the unit you want, then scale you want ( in the system unit setup, button on the window you've opened ).
You can type sizes directly by right-clicking on the scale tool icon. By default it works with %, but you can change that somewhere I think.
To check the size of your mesh ( after having set up the units, of course... ):
-> right panel -> Utilities tab ( the hammer ), select the object ( or objects, you can select more than one, it'll take the farthest points of each mesh ) -> measures ( if it's not in the list, click "more...", it'll be there, take the oportunity to set up the utilities list, things like measures , xform, polycount or addons like texporter are cool, but things like max script or motion capture, I doubt you'll ever use that ).
hope that'll help.