When there is no competent domestic maker, and the foreign supplier is from an enemy state, then the federal government must interfere in the market and create conditions for a domestic supplier. Well, the two logical contenders for such help (Beech and Cesna) were almost helped into the ground by the government, or at least government influencing trial-lawyers, as was mentioned in a post above.
Government getting the hell out of the way is the best recourse, of course we unfortunately have a government that can't stand to keep its hands and noses out of everyone's business and pockets.
Start there.
We can get the Brazilian and Canadian governments' interference in the market out of the way for a start. I'm not suggesting corporate welfare for Beech etc. Just a stop to Canadian and Brazilian corporate welfare to Bombardier and Embraer, which our gov't can facilitate quite easily.