FWIW, the original Terminal 1 at Sky Harbor was an old military bldg. When they finally quit using it, rather than re-number the terminals, they just dropped the Terminal 1 designation. But I agree with you, the rental car return signs at Sky Harbor could use some clarifying - especially for the companies that have returns at more than 1 terminal. Nothing more frustrating than to finally find the right company, only to be at the wrong terminal.