I don't know how to add aircraft to the selection list in "Create a flight"
This link tells you how to add aircraft but what does it have to do with My Traffic 2004.
In the aircraft.cfg Files you get from My Traffic 2004 there are Panel, Model and Sound Files, meaning that all the aircraft are also add-on aircraft, not just AI Traffic.
For instance, if u click on the aircraft.cfg file A346MY, there are subfiles under it that would appear in an add on, like "Panel", "Model", "Sound", and "Texture"
I think i accidentally installed an ATR72 for Delta Connection and American Eagle that came with My Traffic because one day I was looking through my create a flight aircraft list and I found it there, and I know it waz from My Traffic because it said "Licensed by My Traffic 2004" or something like that in the description window, and THAT is what has got me on this 'quest' to install all these aircraft that came with the program into FS2004.
Interesting, but they probably don't have the high LOD that normal downloads do.
iight, but if u saying they bad quality, that's not true because is waz a PROBLEM FREE plane!
LOD is Level Of Detail, how the outside of the aircraft looks, sharp or fuzzy. The sharper it is the higher the LOD the bigger the FPS hit you take.
If they are as good looking as you say then you have hit on a jackpot, enjoy!