Time is a circle

I mean, every once in a while you might end up with a bike instead.

What about those giant quadcopter type things they keep wanting to build to fly from building rooftops in cities for some reason?

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.
- If they really want rooftop travel, a gondola system could probably work.
  
  Works assuming the rooftops are roughly in line of sight. That is something I assumed not to be definitively true in the other comment..
- Oh I mean you can replace them, but when nothing of the original system remains you're not so much optimizing the idea as throwing it out to use trains instead
Everyone thinks the sky is big, without considering just how unscalable flying cars are

no building is designed for large scale entry/exit at roof top. Most don’t support any

the low altitude airspace over a densely populated area is very limited. Given current separation, minimum altitude, speed limitations, a city can support only a small number of flying cars. And no, “smart” vehicles don’t change the laws of physics, even if they help us get closer to them

a flying car will always be more expensive than a not flying car, which will always be more expensive than transit

Let’s stop worrying about new ways for the ultra-rich to avoid the frustrations the rest of us have to deal with, we’ll all be better off if they also have an incentive to design more effective cities and transportation for everyone
- I wasn't, to be clear, advocating for them, just pointing out that they were one of those things tech bros keep suggesting over and over again. I don't suspect they're something to really worry about, because I don't really expect the economics of them to work out.
  
  I wouldn't expect the economics of private jets to work out either, and yet...

What about the moon? Surely not...

Well, ultimately space elevators are the most energy efficient way to escape Earth's gravity well. And once we have one of those, mind as well build a mass driver at the top so rockets don't have to carry so much of their own mass. Then we can build a laser-based photonic sail on the other end to decelerate the cars and make them even lighter/faster, and then build track at the bottom...

Train.

What about interstellar travel?

Well, ultimately wormholes are way more efficient than any subluminal travel once the infrastructure to build them is in place: https://www.orionsarm.com/eg-article/48545a0f6352a

So we control traffic on each side carefully. In fact, we could just suspend a really strong wire on either end...

Yep. Train.

And once we have one of those, mind as well build a mass driver at the top so rockets don’t have to carry so much of their own mass.

You wouldn't even need a mass driver. You have to build your space elevator so that it's center of mass is where you want it to orbit. Logically, this needs to be at geostationary orbit so that the end point on the ground stays in the same spot. That means you can extend the other end of the elevator to twice geostationary orbit. Lift a mass from the ground to the far end of the elevator and just let it go. It will be flung away out of earth orbit because it'll already be moving faster that orbital velocity at that height. You're limited in the direction you can fling it because it will be flung off by the Earth's rotation, but you don't necessarily need a mass driver.
I mean, currently both space elevators and wormholes (as transportation) seem physically impossible.

If we're not sticking to the realm of our current understanding of physics, then that opens the doors for techbros too, because we're in the realm of speculative fiction and things can be however we say they are.
- They're physically possible, just massive engineering challenges. Read Orion's Arm's overview, it's largely based on current known physics.
  
  For space elevators, to the best of my knowledge, there is no known material that can withstand the forces involved. Not even CFNTs.
  
  For wormholes, we're getting so deep into speculation that the conversation doesn't even really matter.

The problem is "perfection" looks different to different people.

If you're optimizing for efficiency, then you're absolutely correct.
If you're optimizing for convenience then shit like personal taxi drones is probably gonna be better.

Trains are extremely convenient. You optimize them for convenience by adding more trains.
- That's how you get to cars.
  
  Add more trains.
  The trains now need to seat fewer people so make them smaller. Maybe 2-7 people per train.
  Most routes aren't needed at any given time, so you might as well only run the train when someone needs it.
  Rather than keeping the unused trains in a central depot, keep them at the departure points
  We can't staff all these trains, and if the departure points are peoples' homes, then let's have the people themselves drive it
  The network of destinations requires a TON of rail switches, and coordinating that is a complicated. Better to use a technology that doesn't require switches, like wheels on pavement.
  
  Boom, cars.
  
  So it really depends on what you're optimizing for.
- And walkability.
  
  When I first moved to Boston many years ago, I had some enlightening experiences. I loved how walkable Boston is, I loved trains, but I did not expect the the feeling of freedom I got from leaving my door with only a T pass in my wallet and Having so much of the city so convenient.
  
  It was revelatory just how much more convenient that was than using a car, when all my life I expected to use a car to go practically anywhere. The challenge is sharing this experience among others who have only known car life, making the advantages real, immediately beneficial.
And yet a coordinated approach with multiple strategies will most effectively cover every use case.

conservatives get too attached to personal vehicles as the strategy they are most familiar with, most focussed on

too many transit advocates recognize the limitations of personal vehicles and the advantages of rail, but tend to speak in absolutes that scare conservatives.

Yes it’s critical that we refocus much of our transportation effort to give more people better choices in more scenarios, but that will never rule out cars
- The point I was trying to make was that tech bros are almost certainly trying to optimize for convenience, because they live in a bubble where thats what's important to them (or that's what has the highest margins).

Issue is, tech bros want "individual pods", with some futuristic look.