United Airlines Orders 15 Supersonic Jets

Fly the friendly skies at twice the speed, on sustainable fuel

United BOOM floght


United Airlines ordered 15 of Boom's "Overture" supersonic jets for $200 million a pop, subject to Boom meeting United's "demanding safety, operating and sustainability requirements." Boom's jet, which is aiming for service in 2029, has not been built or certified.

According to Boom's press release:

"Capable of flying at speeds of Mach 1.7 – twice the speed of today’s fastest airliners – Overture can connect more than 500 destinations in nearly half the time. Among the many future potential routes for United are Newark to London in just three and a half hours, Newark to Frankfurt in four hours, and San Francisco to Tokyo in just six hours."

Treehugger is conflicted. On the one hand, we complain incessantly about the carbon footprint of flying, about how a few rich people are filling the skies with carbon, and how we should all just stop doing it.

Boom in Flight

But with Boom, it is a whole new world of green sustainable flight. Blake Scholl, Boom Supersonic founder and CEO, says of the United deal: "The world’s first purchase agreement for net-zero carbon supersonic aircraft marks a significant step toward our mission to create a more accessible world." It's net-zero because the plane is optimized to run on 100% sustainable aviation fuel (SAF).

Unlike the Concorde SST, which flew commercial flights from 1976 to 2003 and burned through about 7 times as much fuel per passenger as a regular jet, the Overture is going to be really efficient, burning no more fuel per person than a current business class passenger. (A World Bank study calculated that the business class footprint was 3.4 times that of a coach seat because they took up more space and had bigger baggage allowances.)

Boom plane hangar

And hey, it's running on SAF. In his conversation with Dan Rutherford of the International Council on Clean Transportation, Sami Grover asked if SAFs could live up to the hype, and wrote:

"Rutherford added that the problem with waste-based biofuels, which many of the current airline initiatives appear to emphasize, is that supply is massively limited. The industry also has to compete with countless other societal uses for these products. Meanwhile, using renewable electricity to create synthetic kerosene (electrofuel) has more potential, but would require an astronomical build-out of renewable energy capacity – at a time when we are not yet decarbonizing the rest of our electricity demand hard or fast enough."

Can there possibly be enough lard, beef tallow, and schmaltz to keep a fleet of SSTs up in the air? Or is it just wishful thinking and greenwashing, with them ending up dropping conventional fuel into the plane because there isn't enough SAF?

In a previous press release, Scholl noted:

"Policy incentives will play a critical role in accelerating production and adoption of SAF, which is a key contributor to the sustainability of long-haul aviation. Boom supports measures such as blender tax credits to accelerate production of SAF, and the company is working with a broad coalition of fuel producers, operators, airports, and manufacturers to advance this key policy."

Yes, but before the pandemic, the industry burned 95 billion gallons of jet fuel per year and produced 1.7 million gallons of SAF.

Then there is the small matter that when the SAF burns, it is still emitting products of combustion including carbon dioxide, carbon monoxide, nitrogen oxides, and black carbon, twice as high in the atmosphere as conventional planes. The CO2 doesn't "count" because it is not fossil carbon, but this is a distinction that makes less sense every day, especially if it is a waste-based biofuel; raising all those animals has its own carbon footprint.

United flying

But then we cannot forget the most important sustainable benefit of supersonic flight, human flourishing. Scholl noted in a blog post:

"While it is important to preserve mankind’s ability to flourish on our planet, it is also important to extend that ability. A key part of this flourishing, in our view, is supersonic travel."

Scholl says "the pursuit of ever-faster travel speed is really a moral imperative." We can think of some other moral imperatives that should have higher priority.

View Article Sources
  1. Bonfinger, Heinrich, and Jon Strand. "Calculating the carbon footprint from different classes of air travel (English)." The World Bank, 2013.

  2. "Sustainable Aviation Fuels (SAF)." ICAO Environment.

  3. Mazareanu, E. "Commercial airlines worldwide - fuel consumption 2005-2021." Statista, 2021.