I see a well established conversation here - may I add a thought as a new poster?
For me the answer to the "I am a ...." question is either what I get paid to do, or what people would generally describe me as, if they knew me well.
Chuck, if you earn your weekly income by teaching flying skills, then I suppose you are a flight instructor. Presumably you, like Dudley, have the specific qualification that allows you to teach those skills legally, as a consultant or advisor or any other capacity.
But if the rest of the world actually describes the work you do as "airline simulator instructor" then it would be a little misleading to say otherwise. Not wrong, just misleading. (That's just an example - obviously I don't know what work you actually do right now!)
Better just to say what you do. Sometimes that might mean avoiding a term like "flight instructor" that carries strong connotations.
Cheers,
O8