This is from Legal Heat and applies to AZ state law.
Public and private schools A.R.S. § 13-3102.A.12 (see A.R.S. § 13-3102.C & J or "Special Notes" below for exceptions)
The above prohibition for firearms in school zones does not apply to a: "Firearm that is not loaded and that is carried within a means of transportation under the control of an adult provided that if the adult leaves the means of transportation the firearm shall not be visible from the outside of the means of transportation and the means of transportation shall be locked." Ariz. Rev. Stat. Ann. § 13-3102.
I have a CCW permit. Can I carry my handgun on school grounds while picking up my child?
Conditionally. If you remain in your vehicle and the handgun is unloaded before entering school grounds, yes. If you have to exit your vehicle while picking up your child, the handgun must be unloaded (as above) and secured (locked) within the vehicle out of plain view. Use caution if you must exit the vehicle with a handgun (or any weapon) to secure it in the trunk of your vehicle. Others may see you and not understand your intention.
Additionally, designated employees of a school may order a person off of school property if that person is believed to be interfering with school operations. School boards may also enact specific and more restrictive rules governing firearms and deadly weapons on school grounds. Determine what the rules of a school are before attempting to enter school grounds with a firearm. (ARS 13-3102.A.12, 13-3102.I and ARS 13-2911)
Arizona Department of Public Safety
P.O. Box 6638
Phoenix, AZ 85005