According to the Arizona Department of Motor Vehicles, out-of-state students enrolled with 7 or more units per semester are not considered Arizona residents (https://www.azdot.gov/mvd/VehicleServices/Registration/registration-compliance-violators) and do not need to license their vehicles in Arizona.
Out-of-state students with a vehicle manufactured between 1966 and 2010 must take the vehicle to one of the local emissions stations (http://www.myazcar.com/) and bring a copy of your student schedule, indicating enrollment for 7 or more credit hours. If the vehicle passes emissions, the student will pay .25 and receive and excemption sticker. If the vehicle was manufactured after 2010, the student may go to any ADOT MVD office (http://www.myazcar.com/) with a copy of the course schedule, indicating enrollment for 7 or more credit hours, and pay the .25 fee to receive the exemption sticker.
If the vehicle is registered to someone other than the student, student must provide a power of attorney letter.