Drawing Airfield Layouts

Jon,

I could'nt get the hang of Auto CAD (in DOS days!) and found it too fiddly. As you use it on a daily basis I assume it is a lot easier. As you can see from the previous posts a lot of us have become fans of Paint.NET and it seems to do pretty much what you describe. The most difficult thing I found in the past was curves and this is not a problem any longer. They key thing is to use what you feel comfortable with and it sounds as though Auto CAD works for you.
The layers thing is probably the most critical aspect and when I drew the Gaydon layout I had multiple layers including OS and a couple of drawings from the National Archives. The OS layer was for map accuracy and TNA layers for wartime layout. There was a lot of compromise though.
My next project is to "sketch" Mildenhall as it was in 1941/2. I will probably post the result so keep an eye out over the next few weeks/months/years.
I also use a mapping service but have found the major drawback is the size of output. It requires a number of tiles to get a whole airfield site so as you say it is very expensive. As a result I haven't used it much despite the excellent coverage of the 1950's and 1960's. I think it is geared to large companies rather than individuals for research.