This will revolutionize the delivery industry. I imagine trucks will become mobile drone carriers with drones landing and taking off with packages as they travel through the city.
I have a lot of doubts on the cost/efficiency of this. Keeping things airborne will always cost a lot more energy than rolling things around. Ground-based delivery robots make some sense, air-based ones likely don't.
flight is appealing over ground based drones as one delivery truck or base station could concurrently service multiple blocks with lower risk of someone abducting or damaging the drone. Although in all honesty I'm not sure if weight, range, carrying capacity, or speed would work out in a compelling form factor.