No part of Tesla cars requires the use of mobile networks for basic car operation. It is just the extended functions such as pre-cooling the car remotely, or in

No part of Tesla cars requires the use of mobile networks for basic car operation. It is just the extended functions such as pre-cooling the car remotely, or initiating "Smart Summon" (to have the car drive to you from across the parking lot) that requires mobile network connectivity. If you just want to do typical car stuff like drive somewhere you don't need cellular or Wi-Fi.