Its reasonable that if he saw a vision of that turbo prop plane that he would call it a jet in the way that he did.
It may not be technically right to call it a "jet" to most of us more familiar with aircraft but it is entirely possible that someone could call all aircraft "jets".
In addition I have heard turboprops called "jetprops" as in the old days they replaced a piston engine with what is the heart of a "jet" engine -- the turbine.