Can I target AIR and Flash simultaneously?

I’m working on a long project that I just brought over to the AIR platform. The problem is, I’m now using classes that the Flash player doesn’t recognize. The player throws errors in global __init(), probably when it’s reading in the import statements.

It’d be nice if there was a way to tell from within the program whether it’s running in Flash or on AIR. I could probably look at the security sandbox type– AIR has a very different sandbox. But even then, I need a way to gain access to the AIR-specific classes after I run the AIR test:

var classA:Class, classB:Class, classC:Class;
if (this is an AIR app) {
classA = getClass("AIRClassA");
classB = getClass("AIRClassB");
classC = getClass("AIRClassC");
}

Something like that. I’m guessing GetDefinitionByName() will work, but I’m not sure. Any ideas?