There are several companies and organizations around the world working on flying cars, and if they succeed cities will need to adapt.

If you were a fan of science-fiction growing up, there’s a good chance that you are harboring a tiny shred of resentment at some of the technology that we assumed was a given, but has yet to materialize. That includes hoverboards, robot sidekicks, and – of course – flying cars. While there has been some progress on the hoverboard front and robot friends are coming along, flying cars are still a few years out at least. And when they do arrive, they will require a significant shift in how we plan out our cities.

Currently, there are dozens of groups around the world that are working on some form of flying cars. Dubai is currently testing flying taxis, Uber plans to have flying cars on demand by 2020, and plenty of major automakers are looking at ways to get in on the action as well. When the 2020 Olympics hit Tokyo, the plan is to light the Olympic Torch from a flying car developed in conjunction with Toyota. And if there wasn’t a rush to take us to the air before then, having hundreds of millions, if not billions of people see the potential of flying cars during the Opening Ceremonies should ignite passions.

Flying Cars are Coming, and Cities Need to PrepareBut flying into an open stadium is relatively easy – not technologically speaking, just in terms of logistics. The car will have a set route and it will, presumably, be the only flying car in the area. But what happens when there are dozens of flying cars in the air, even hundreds? It might sound simple enough to make your way through the wide-open areas above a city, but there are countless dangers awaiting drivers in the sky. And the more people take to the air, the more dangerous it will become.

There’s a good reason helicopters can’t just fly anywhere they want, and it’s not just to avoid freaking people out. Look out any window in a major city and you may see construction for a huge building underway. You may even see a crane on top of that building. From a distance, that’s easy to call out, but flying through the streets with buildings obscuring your view, the chances of an airborne collision increase. And what about parking? Will flying cars have their own landing pads, or will they be fighting with conventional traffic for spots? If you think parallel parking in a big city is bad now, imagine having to fight off someone from above as well. And this all overlooks the biggest issue, the possibility of a flying car crashing, which would be bad news for the driver, of course, not to mention all the people on the ground where it comes down.

So far there is no consensus on how to handle these issues. Granted, they are still just hypotheticals at the moment, but by 2020 it looks likely that there will be some flying cars in operation and that will force city planners to make decisions.

For now, it appears that flying cars will be regulated in a somewhat similar fashion to drones, meaning they will have some restrictions and they will need approvals to travel certain routes. As the number of flying cars ramps up, however, it won’t be practical for multiple drivers/pilots to call in an request a route each and every time they need to go somewhere. When the first flying cars do begin regular service, there may also be specific spots around cities where they can land; they might use specially zoned areas on the street, and/or share helipads. It won’t be a major problem as the numbers are low, but as they increase it will become an increasingly troublesome issue.

Flying Cars are Coming, and Cities Need to PrepareIn cities with ample waterways, flying cars may turn rivers into the highways of the sky in order to give a little extra sense of security to those on the ground, but this is a luxury only a handful of cities could offer. More likely, flying cars will need to stick to – or above – established streets. It might seem easy enough to just fly over all the buildings, but navigating from the air is a much different experience than navigating on the ground. Plus, the higher you go, the more risks you face. Throw in inclement weather and it changes things further.

The majority of currently proposed flying cars are electric and rechargeable, but as the demand grows, there will need to be solutions in place that increase the batteries to make them practical. Cities and/or companies will need to offer recharging stations and adapt current structures to flying cars as well. When flying cars become cheap enough to purchase privately, it might be an easy matter to convert the top floor of a parking structure without a roof into a landing/parking area, but most will need to provide power to the cars. That means that parking structures will need to become energy conscious as well (at least until battery size is no longer an issue), even potentially going as far as to become minor solar farms that can harness enough energy to power both the flying cars of the future, as well as the increase in conventional electric cars.

As buildings become smarter and more connected, that could also help with flying car traffic. As a flying car approaches a smart building, the building could automatically connect and help to direct traffic. Paired with interactive roads, landings could be coordinated with oncoming traffic on the ground to help provide landing spots.

These problems won’t fully manifest for several years at least, but the cities of today will soon need to begin planning for the problems of tomorrow. If not, the future may be a casualty of poor planning.