The supersonic Concorde jet made its last commercial passenger flight on Oct. 24, 2003. The Anglo-French plane was a wonder to watch, but could never overcome its high costs and concerns over its noise.

Is supersonic travel ready for its next act?

In June, United Airlines Holdings Inc. said it would buy 15 small supersonic jets being developed by Boom Technology Inc. Boom hopes to fly a scaled-down prototype of the so-called Overture jets later this year, with the full-size jet ready by the end of the decade.

Boom says the jets would be able to fly at Mach 1.7, or 1.7 times the speed of sound, enabling passengers to fly from London to Newark, N.J., in 3½ hours; it currently takes over six hours. A flight from San Francisco to Tokyo would take six hours, down from over 10 hours.

Proponents say this can happen, if entrepreneurial vision and market forces are allowed to work. Skeptics doubt that the demand will be there, given the likely cost of a ticket.

We invited people on either side of the debate to present their best case. On the pro side: Adam Pilarski, a senior vice president at Avitas Inc., an aviation industry consulting firm. On the con side: Richard Aboulafia, an aviation consultant at Teal Group.

YES: The demand is there if the product is right

By Adam Pilarski

Adam Pilarski

Not only can supersonic flights make a comeback. I’m convinced they will.

Aviation started well over a century ago with the first flight of the Wright brothers on Dec. 17, 1903. That flight lasted 12 seconds, carried one passenger and traveled 120 feet at an air speed of 34 mph.

In the decades that followed, we made tremendous progress in all aspects of aviation: safety, comfort, distance, capacity. And, especially, speed. The weekslong journeys between continents have been replaced with flights of hours.

But the advances in speed stopped after the introduction of jet travel at the end of 1950s. Since then the average speed of flights has remained pretty stable, limiting one of the major benefits of flying.

I think we’re ready for another leap.

This time is different

Let’s begin by addressing the jumbo jet in the room: the demise of the European Concorde.

The Concorde’s failure isn’t an indication of the failure of the idea. It failed for three reasons. First, the sonic boom meant it couldn’t fly over inhabited land, limiting the routes it could fly and its moneymaking potential. Second, the ticket prices were higher than existing products, and passengers got little in return. And that leads to the third reason: The Concorde was a government project whose goal was national prestige rather than a response to market opportunities. There was no effort to create a plane that had the range and comfort customers demanded. The result was a product designed for a small number of government officials and business executives, rather than a truly revolutionary and comfortable product for those who would be willing to pay for it.

And trust me: The demand is there if the product is right. We live in a society where people have less patience and don’t want to wait for anything. Two seconds for a webpage to load? No way! Twenty hours to get to China? Forget it!

Sure, you can work on flights more easily than ever, with internet connections available, but businesspeople are flying because they need to be somewhere in person. Being stuck in the air for 12, 15, 20 hours is increasingly a waste of their valuable time.

Then there are the nonbusiness travelers. The population in more-developed countries is getting richer and older. The number of retirees is going to be exploding in coming years, and those retirees want to see the world—and not spend very long hours on planes.

Price differences

There are, of course, plenty of other arguments as to why supersonic travel won’t take off. I believe none of them hold up to scrutiny.

To start with, there is the price. Yes, difference in prices between supersonic and subsonic travel could be pretty hefty. But these are different products and consumers will look at them differently. Nobody who flies to Europe thinks about the difference in rates between air and ship. They treat them as different products, worth different prices.

Then there’s the question of sustainability. That problem is a real one, but supersonic and subsonic flights are both vulnerable to being curtailed. Aviation engineers know this and are working hard on coming up with solutions. Based on human history, they will come up with dramatic solutions that will allow the continuation of unfettered air travel and protect the environment.

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Skeptics of supersonic travel also point to the issue of limited range of supersonic flights. I agree that if we are limited to existing technology and a range of 4,000 miles, supersonic travel makes no economic sense. But entrepreneurs will aim for longer ranges, and that will lead to now-unimagined breakthroughs. This is always what happens with technology.

Why hasn’t all this happened yet? The industry is inbred and political, with regulations that protect the status quo. The government can play an aggressive role in funding technological advancements in muting sonic boom and helping with alternative fuels. But it also needs to establish the groundwork so that aggressive, brilliant and greedy entrepreneurs can step in and change the future—entrepreneurs for whom supersonic travel isn’t a national vanity project.

We can learn from the car industry. People didn’t believe electric cars would happen because of all the necessary infrastructure demands. We couldn’t imagine a network of charging stations all over the country.

But Elon Musk could and proved it could be done. His first cars were expensive, and yet somehow he managed to overcome all the operational constraints. And some new Teslas are now a third of the original price.

Aviation has been built by dreamers who used innovation to advance our lives. There exist all the elements now to make another leap forward.

It can be done. And it will be done.

Dr. Pilarski is a senior vice president at Avitas Inc., an aviation industry consulting firm. He can be reached at reports@wsj.com.

NO: A connected world has less need for supersonic speed

By Richard Aboulafia

Richard Aboulafia

Supersonic jet travel seems almost like an inevitability. While 14 Concordes stayed in service from 1976 to 2003, the other 40,000-plus jetliners that have been built all flew, or fly, well below the speed of sound. The traveling public can be excused for asking, “What happened to aeronautical progress?”

But there are two big showstopping problems with supersonic air transport. The first problem is fundamental to the air-travel market. The second is a completely exogenous problem resulting from progress in unrelated technologies.

First, there need to be enough of the right passengers on enough routes. There has been progress in making supersonic travel less expensive than in Concorde’s day. But there has been greater progress in making subsonic travel cheaper still. Thus, supersonic travel tickets will still need to sell at a large premium relative to subsonic ones. There is certainly a segment of the traveling public that will likely pay a premium; just look in the front of the plane on any international flight (and exclude people who are there with frequent-flier upgrades, of course).

The Concorde taking off for its final passenger flight, from New York’s Kennedy Airport to London, on Oct. 24, 2003.

Photo: Mario Tama/Getty Images

But how many routes have enough of these passengers? Airlines could certainly put a few 100-seat supersonic jets on flights from New York to Paris, or from Washington, D.C., to London. But only a handful of these business-intensive routes exist. Most international routes are overwhelmingly dependent on cost-sensitive tourists. This problem can’t be solved by merely rerouting business passengers through major hubs: If someone was traveling from Atlanta to Paris, flying them first subsonic to New York and then on to Paris supersonic wouldn’t save much time at all relative to flying them subsonic nonstop from Atlanta to Paris.

Limited range

This first problem is greatly worsened by the fact that supersonic jets are far more range-limited than subsonic ones. High fuel consumption means they’re basically limited to routes no longer than around 4,000 miles. Thus, the crucial routes between Asia-Pacific cities and European or North American cities are off-limits. We’re left with a handful of trans-Atlantic routes—enough to justify production of maybe 50 aircraft, which certainly wouldn’t justify the $20 billion to $25 billion needed to develop a supersonic jetliner.

The second problem concerns communications technology and international travel. Consider passenger travel in the Concorde era. Fliers were completely disconnected from the outside world. Upon landing after a three-hour flight, they’d rush to the nearest pay phone or, in the 1990s, break out their cellphone, and ascertain what they’d missed. Business travelers, particularly those employed in the financial sector, were deeply grateful to have only missed three hours of global or industry developments, rather than the seven or eight they’d miss on a subsonic flight.

But today, onboard communications allows people to stay connected in real time. This capability is only getting better, and there really isn’t much difference between an office in the sky and an office on the ground. Also, supersonic jets will always be more space-constrained than subsonic ones (due to the need to minimize drag); as with the Concorde, travelers will to have a reclining seat that’s slightly larger than those found in premium economy. But passengers in the front of a subsonic jet have their own office pod, with a lie-flat seat, personal in-flight entertainment, electrical connections and often even a small work area. Unlike in the Concorde’s day, travelers carry computers that are the same as found in their terrestrial office.

End of a startup

In other words, a passenger today has much less incentive to pay more to travel at supersonic speeds. It was this dynamic that helped kill Aerion, the world’s most advanced supersonic private jet startup, earlier this year.

These two problems, along with others (the sonic-boom problem has yet to be solved, and supersonic flying is bound to be a lightning rod for environmentalists’ anger), have produced a strange industry landscape. The two companies that build 95% of the world’s jetliners— Airbus and Boeing —have zero interest in a creating a supersonic jetliner, despite having all the necessary financial and engineering resources (both companies have experience building supersonic combat aircraft). The other jet players—Russia’s UAC, China’s Comac, and Brazil’s Embraer—have no interest either. Most supersonic startups have expressed interest in a supersonic business jet, a very different idea.

That leaves Boom Technology, with its Overture concept aircraft. It has, by its own account, raised $270 million in seed and venture capital. This is just a small part of the overall development bill. Given the problems supersonic travel faces, raising the remaining money needed to bring a jet to market is, I am convinced, far out of reach.

Mr. Aboulafia is vice president of analysis at Teal Group. He can be reached at reports@wsj.com.

United Airlines' announcement that it plans to buy 15 supersonic aircraft from the startup Boom Supersonic is raising questions about the future of ultra-fast plane travel. In this video, WSJ speaks with an industry analyst to better understand what’s next for faster-than-sound air travel. Photo: Boom Supersonic The Wall Street Journal Interactive Edition