Ahh! Looking better all the time.

Are you using that 3-view as a visual guide, or have you made your own backdrops to stick in Gmax? I do believe there is a tutorial by Katahu in the downloads section somewhere that will show you exactly how to edit a 3-view and position it to where you are able to use it very accurately to "trace" the aircraft.
When building a Gmax model, I tend to use several different scenes for each aircraft: one for each major section. Wings, fuselage, cockpit, etc. I then
merge each section so that I end up with a complete aircraft. I also section out the interior and exterior models, so that I do not get confused on which part goes with which model. I keep them in seperate scenes as well. I merge from the fuselage-wings-cockpit scenes into both the interior and exterior scenes, then do my major linking (connections to exterior and interior dummies) there. Then I merge into one single "merge" file that has everything included in it.
Doing this prevents me from overwriting certain bits of the aircraft and being unable to figure out where they ended up at. I am also able to prevent some unknown issue that occasionally pops up using Gmax. It will occasionally give an error that is unacountable and that no amount of tweaking will overcome. At this point, the file I am working with is effectively useless. So I have to trash it. With multiple scenes, each containing a different part of the aircraft, I can move ahead with a certain part, confident in the fact that I will not lose that data when some other bit in the model goes topsy-turvy.
All the above says: make multiple backup scenes. Save frequently, with different file names.