I think it's fake.
I did some research, Gen. Thurman is real (wiki)
However on the bottom it says the Onion article was satire.
It does look like satire.
He said "cmon just one little airstrike in Houston". That's totally not a realistic sounding quote given the context imho, it seems to "jokingly"
in the first place.
Let's apply some common sense here and put this in the joke bin until actual evidence surfaces (which I seriously doubt it will).