Ariz. Rev. Stat. § 28-142
The regulation and use of livery vehicles, taxis, transportation network company vehicles, transportation network companies and limousines are of statewide concern. Livery vehicles, taxis, transportation network company vehicles and limousines and their use and transportation network companies that are regulated pursuant to this title are not subject to further regulation by a county, city, town or other political subdivision of this state, except that a public airport operator that operates a public airport pursuant to section 28-8421, 28-8423 or 28-8424 or a public body operating a public airport may establish the number of livery vehicles, taxis, transportation network company vehicles, transportation network companies or limousines that may conduct business at a public airport or may set additional or more restrictive requirements for the conduct of that business at a public airport.
A.R.S. § 28-142