Air filter on 2005 Toyota Highlander. where is it and is there only one?

If you're asking about the engine air filter, it is located enclosed in a black plastic box slightly to the right hand side of the engine compartment (as viewed from the front grille area).

There is another filter, but it is the cabin air filterfor the heating and A/C air entering the passenger compartment. THAT is located behind the glove box assembly.