Hi Gene, could you add some more info? Like what aircraft cockpit are the plans for (F-15?) and would electrical plans and how-to's be included? I think it would avoid downloads that would be deleted afterwards, if they find out it's not what they're looking for.
For AutoCAD files there's always Autodesk's own
DWG TrueView, or if someone wants to make some changes to them they could use a 30-day ProgeCAD trial.