This is one of my passions, along with wireless mesh networks - p2p delivery.
The dispatching system can easily be a DAC, basically a market place for matching vehicles to users. Each vehicle could be a DAC with shareholders or shareholders had own a fleet of vehicles through a DAC. Vehicles can be protected from theft and vandalism by users temporarily purchasing the vehicle with DAC shares for delivery and reselling it back to the DAC or another user minus delivery fee after delivery is complete. Service operators may purchase, refuel, recharge, and repair, and the resell vehicles into the transport network at a profit. Operators may also lease vehicles at a mark-up to users who can't or don't want to temporarily purchase vehicles for a delivery.
The vehicles would be open source design with standardized interface among parts, like PC computers, so anyone can build vehicles and sell them into the network.
The vehicles can be both wheeled autonomous vehicles and drones. I would redesign the drones to be quad or more fans for vertical takeoff and landing with a lifting body for fast, efficient, horizontal flight.