Where is the Air Zalagasa desk?

Hint 1 of 4:

Remember the way this whole game works -- whatever happens is the opposite of
what you'd expect.

Hint 2 of 4:

Think this way when you look at the signs.

Hint 3 of 4:

Go at the entrance to the airport, and go east and west while looking at the
signs.

Hint 4 of 4:

Keep going north when you find the one sign that DOES NOT mention Air
Zalagasa.