Within cities?
Look, aircraft are Hella noisy and if stuff goes bad, they’ll smash into buildings. Using them for intra-urban transit is not safe. Besides, I don’t know if multicopters can autorotate[1], which only adds to the safety concerns.
So why not bring it slightly closer to the ground. Maybe put the transportation device on a bridge or viaduct. And while you could put some stairs up from the streets, you may even choose to link buildings into them directly. Most tall buildings have lifts, after all.
Next, giving each building its own link into the system would be excessive. You can achieve 90 percent of the utility if you have larger entry hubs for multiple buildings, and expect people to walk the last mile.
Anyway, back to the vehicle, since a vehicle for a handful of people is rather inefficient, why not build the vehicles for many dozens of people? Why not build it to connect multiple vehicles? If you run, like, four of these, every five minutes, most people will be able to walk up any time and just go.
And to make that movement more efficient, let’s have our vehicles roll along a specifically designed path, optimised for minimal friction by using hard wheels on a hard surface.
There, I replaced the quadcopters with a train.
EDIT:
[1]: According to one answered question on a StackExchange page, the answer to this question is probably no. Autorotation requires some magnitude of control of the pitch of your rotors, something that most multicopters do not have.
It does make me intrigued to see what’d happen if you could or did fit a multicopter with swashplates and pitch-adjustable rotors.
Works assuming the rooftops are roughly in line of sight. That is something I assumed not to be definitively true in the other comment…