Brandon Donnelly
Daily insights for city builders. Published since 2013 by Toronto-based real estate developer Brandon Donnelly.
Brandon Donnelly
Daily insights for city builders. Published since 2013 by Toronto-based real estate developer Brandon Donnelly.
As a general rule, building a new building is easier than trying to do surgery on an existing one, because you never know exactly what you're going to find when you start the latter. But there are instances where surgery is necessary.
According to Bloomberg, developers in London are becoming increasingly interested in the airspace above existing buildings, and it supposedly started because of some policy changes:
In 2020, then housing minister Robert Jenrick introduced reforms that relaxed rules to add airspace builds above existing buildings. Owners can now construct additional residential stories to either expand their own dwelling or to create new units altogether without going through full planning permissions, which are often a long and costly process. This was part of a broader set of reforms to boost housing supply, and the current Labour government has not shelved these changes.
Here's an example site listed for £150,000:
The site currently comprises the roof and airspace above a 3-storey mixed-use residential-led block (Block B) within The Glassworks Development.
The existing development was constructed in 2017 and comprises 23 residential apartments plus ground floor commercial space, all of which are sold off on long leases.
I had an old boss who was very interested in this idea. For him, it was "free" land and a way to further extract value from an existing real estate portfolio. Of course, it's also a way to build new homes in already built-up cities. Some industry people think that London could accommodate up to 180,000 new homes using this strategy.
But these are not simple builds. Can the existing structure and foundations support additional levels? How do you modify the existing elevator(s) while the building below remains occupied? How do you do the mechanical tie-ins without impacting the suite(s) below?
All of this makes me wonder how feasible it will be for London to build 180,000 new homes in this way. If it can, that would be a great accomplishment, and one that other cities should aim to emulate. But regardless, I'd love to get under the hood of one of these projects.
Cover photo by Travis Fish on Unsplash
Whether you live in North Dakota or Texas, there's a reasonable chance that when you travel internationally, you enjoy going to Cancun. Or perhaps you fly into Cancun and then go to a neighboring town like Tulum. United Airlines just released the following map showing the most-booked international destinations from every state for passengers traveling on United Airlines between January and October 2025. The top three destinations are London, Cancun, and Tokyo:
As a general rule, building a new building is easier than trying to do surgery on an existing one, because you never know exactly what you're going to find when you start the latter. But there are instances where surgery is necessary.
According to Bloomberg, developers in London are becoming increasingly interested in the airspace above existing buildings, and it supposedly started because of some policy changes:
In 2020, then housing minister Robert Jenrick introduced reforms that relaxed rules to add airspace builds above existing buildings. Owners can now construct additional residential stories to either expand their own dwelling or to create new units altogether without going through full planning permissions, which are often a long and costly process. This was part of a broader set of reforms to boost housing supply, and the current Labour government has not shelved these changes.
Here's an example site listed for £150,000:
The site currently comprises the roof and airspace above a 3-storey mixed-use residential-led block (Block B) within The Glassworks Development.
The existing development was constructed in 2017 and comprises 23 residential apartments plus ground floor commercial space, all of which are sold off on long leases.
I had an old boss who was very interested in this idea. For him, it was "free" land and a way to further extract value from an existing real estate portfolio. Of course, it's also a way to build new homes in already built-up cities. Some industry people think that London could accommodate up to 180,000 new homes using this strategy.
But these are not simple builds. Can the existing structure and foundations support additional levels? How do you modify the existing elevator(s) while the building below remains occupied? How do you do the mechanical tie-ins without impacting the suite(s) below?
All of this makes me wonder how feasible it will be for London to build 180,000 new homes in this way. If it can, that would be a great accomplishment, and one that other cities should aim to emulate. But regardless, I'd love to get under the hood of one of these projects.
Cover photo by Travis Fish on Unsplash
Whether you live in North Dakota or Texas, there's a reasonable chance that when you travel internationally, you enjoy going to Cancun. Or perhaps you fly into Cancun and then go to a neighboring town like Tulum. United Airlines just released the following map showing the most-booked international destinations from every state for passengers traveling on United Airlines between January and October 2025. The top three destinations are London, Cancun, and Tokyo:
First, it's important to keep in mind that this data only includes people flying on United; it doesn't capture all international air travel. Second, maps like this are necessarily going to be influenced by an airline's biggest hubs. In the case of United, its hub-and-spoke model relies on major airports and routes like San Francisco-Tokyo and Newark-Heathrow.
Still, specific destinations appear on this map for a reason. Cancun is the number one "vacation" airport for Americans, which is an incredible success story, because it wasn't a place until the 1970s. Prior to Cancun, Acapulco was Mexico's top resort destination, but it was becoming constrained, and the government needed a replacement conduit for extracting US dollars from the American middle class. So, they developed Cancun.
The popularity of Tokyo is likely partly a result of a weaker yen, in addition to being an important Asian hub and an incredible place to visit. According to the Japan National Tourism Organization (JNTO), over 2.7 million Americans visited the country in 2024 — a 33% year-over-year increase and a 58% increase compared to 2019.
The country also saw 3.7 million international visitors in January 2025, which is the highest ever for a single month. Countries like the US and Canada also set all-time records for January arrivals. Part of this, I'm sure, has to do with Japan's legendary "Japow." I was part of this year's cohort, and I've never seen so much snow as I did on the island of Hokkaido.
There are also very specific one-off relationships that appear on United's map. The number one destination for the state of Arizona is, for example, Taipei. And this is being driven by a semiconductor boom, specifically Taiwan Semiconductor Manufacturing Company's direct investment in the state. At the time, it was heralded as "the largest foreign direct investment in a greenfield project in American history."
So, there's a lot that can be gleaned from a map like this. If we were to zoom out and look at all international air travel, we would likely see some reordering. I suspect Paris would jump ahead of airports like Vancouver, given its hub status for other airlines. But it's unlikely you'd see a completely different list. Americans fly east to London, south to Cancun, west to Tokyo, and north to Toronto. These are the primary hub airports.
Nationwide across the US, transit ridership is only at about 70% of where it was in 2019 before the pandemic. But this is not the case in all cities around the world. According to this recent Bloomberg article, Madrid, Hong Kong, and Paris are all above their 2019 ridership levels. Seoul and Shanghai are also close at just over 90%, and London is at 85%.
So this problem of fewer people riding transit seems to be a North and South American phenomenon. Rio de Janeiro is at 73%, Mexico City is at 70%, and San Francisco is somewhere near or at the bottom at 44%. The obvious explanations for this are that Europe and Asia are generally denser and less car-oriented, their return-to-office patterns have been much stronger (less WFH), and their governments probably care more about transit (and spend more money on it).
Broadly speaking, I think this is all true, but I'd love to know more precisely what's driving these differences. Because it's not exactly obvious. Consider, for example, Paris and London. Paris is at 103% of its 2019 levels, whereas London is only at 85%. Why is that? Both cities share a lot of similarities. They have a river that weaves through the middle, they're dense, they have lots of trains, and both are alpha global cities.
So why the delta? What exactly is Paris doing that is encouraging more transit usage?
Charts via Bloomberg
First, it's important to keep in mind that this data only includes people flying on United; it doesn't capture all international air travel. Second, maps like this are necessarily going to be influenced by an airline's biggest hubs. In the case of United, its hub-and-spoke model relies on major airports and routes like San Francisco-Tokyo and Newark-Heathrow.
Still, specific destinations appear on this map for a reason. Cancun is the number one "vacation" airport for Americans, which is an incredible success story, because it wasn't a place until the 1970s. Prior to Cancun, Acapulco was Mexico's top resort destination, but it was becoming constrained, and the government needed a replacement conduit for extracting US dollars from the American middle class. So, they developed Cancun.
The popularity of Tokyo is likely partly a result of a weaker yen, in addition to being an important Asian hub and an incredible place to visit. According to the Japan National Tourism Organization (JNTO), over 2.7 million Americans visited the country in 2024 — a 33% year-over-year increase and a 58% increase compared to 2019.
The country also saw 3.7 million international visitors in January 2025, which is the highest ever for a single month. Countries like the US and Canada also set all-time records for January arrivals. Part of this, I'm sure, has to do with Japan's legendary "Japow." I was part of this year's cohort, and I've never seen so much snow as I did on the island of Hokkaido.
There are also very specific one-off relationships that appear on United's map. The number one destination for the state of Arizona is, for example, Taipei. And this is being driven by a semiconductor boom, specifically Taiwan Semiconductor Manufacturing Company's direct investment in the state. At the time, it was heralded as "the largest foreign direct investment in a greenfield project in American history."
So, there's a lot that can be gleaned from a map like this. If we were to zoom out and look at all international air travel, we would likely see some reordering. I suspect Paris would jump ahead of airports like Vancouver, given its hub status for other airlines. But it's unlikely you'd see a completely different list. Americans fly east to London, south to Cancun, west to Tokyo, and north to Toronto. These are the primary hub airports.
Nationwide across the US, transit ridership is only at about 70% of where it was in 2019 before the pandemic. But this is not the case in all cities around the world. According to this recent Bloomberg article, Madrid, Hong Kong, and Paris are all above their 2019 ridership levels. Seoul and Shanghai are also close at just over 90%, and London is at 85%.
So this problem of fewer people riding transit seems to be a North and South American phenomenon. Rio de Janeiro is at 73%, Mexico City is at 70%, and San Francisco is somewhere near or at the bottom at 44%. The obvious explanations for this are that Europe and Asia are generally denser and less car-oriented, their return-to-office patterns have been much stronger (less WFH), and their governments probably care more about transit (and spend more money on it).
Broadly speaking, I think this is all true, but I'd love to know more precisely what's driving these differences. Because it's not exactly obvious. Consider, for example, Paris and London. Paris is at 103% of its 2019 levels, whereas London is only at 85%. Why is that? Both cities share a lot of similarities. They have a river that weaves through the middle, they're dense, they have lots of trains, and both are alpha global cities.
So why the delta? What exactly is Paris doing that is encouraging more transit usage?
Charts via Bloomberg
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