The return to flying faster than sound will start small

The Federal Aviation Administration is resurrecting the dream of passengers flying faster than the speed of sound after it recently proposed lifting a ban on supersonic flights over land, which has been in place for more than five decades.

The catalyst for the proposed rule change, which is now open for public comment, comes from data collected on flights of NASA’s X-59 aircraft, an experimental supersonic plane built by Lockheed Martin Corp. This long, sleek jet began flying in October to test a design that mitigates the continuous boom that takes place when an aircraft breaks the Mach 1 sound barrier, which is about 678 miles an hour at an altitude of 30,000 feet. The X-59 flies as fast as Mach 1.4 and reduces the boom to a muted thud that shouldn’t disturb people on the ground too much.

Commercial passengers haven’t been able to break the sound barrier since the Concorde, which operated from 1976 to 2003. The plane’s four engines guzzled fuel at low speeds, and the aircraft rattled windows and set off car alarms when landing or taking off. The plane was limited to a handful of airports because of the noise and was retired because of economics and safety, especially after a July 2000 accident that killed all 109 passengers and crew as well as four people on the ground soon after takeoff near Paris.


It seems almost absurd that commercial flyers had an option to travel much faster in the 1970s than today. The decades it has taken just to get to the discussion about lifting the overland ban speaks to the complexity of the physics and the huge risks any aircraft maker would undertake to build a civilian plane that flies beyond the speed of sound. There will be no mad dash to build such an aircraft, and it’s highly unlikely to start with an airliner. If the overland bans are lifted in the US and Europe — whose regulator, the International Civil Aviation Organization, will need to get on board — the return of civilian supersonic travel likely will come as a private jet.

The market is large enough among high-net-worth individuals, private-jet fleet operators and heads of state — customers willing to pay a high price for speed or bragging rights — to provide the required volume for such a plane to be profitable, Rolland Vincent, an aviation consultant, said in an interview. Engineers will have to figure out how to create that sleek design that mitigates the boom while providing space in the cabin for at least eight passengers who have room to stand up, said Vincent, who has done work for clients to study supersonic opportunities.

The first mover on a supersonic civilian aircraft will have a big advantage because of the limited addressable market. A successful private jet that breaks the sound barrier would then pave the way for one of the large aircraft makers to eventually enter the fray, widening the market to hundreds of airline customers and much higher volume.

Only a handful of aircraft makers have the finances, the reputation and the engineering prowess to make the first move. General Dynamics Corp.’s Gulfstream is the largest US maker of private jets by revenue and has studied a supersonic design in partnership with NASA, including tests on its famous quiet spike. France’s Dassault Aviation SA makes large corporate jets and supersonic military aircraft. Textron Inc. makes small private aircraft, including the Cessna jets and military training planes.

Canada’s Bombardier produces the largest purpose-built corporate jet and sells some of its most popular models to militaries. In fact, Bombardier brags that its Global 8000 is now the world’s fastest civilian jet with a top speed of up to Mach 0.95, just below the sound barrier. Brazil’s Embraer SA makes private jets, small airliners and military aircraft. The company this year began assembling supersonic military jets, with partner Saab, in Brazil.

Airbus SE and Boeing Co. both make large airliners and military jets. You can bet that when the technology is mature enough to produce a profitable supersonic airliner, they will be at the forefront.

The key to any supersonic project will be the engine makers, which are an even more select group. GE Aerospace, RTX Corp.’s Pratt & Whitney, Safran SA and Rolls-Royce Holdings Plc make commercial airliner engines and military power plants for US and European fighter jets. Honeywell Aerospace and Williams International manufacture engines for small private jets. Without a top engine maker as a partner, any effort to build a supersonic civilian aircraft isn’t a serious project.

The industry has been down this road before. Texas billionaire Robert Bass founded and funded Aerion, a supersonic private jet startup that teamed up with GE as an engine partner. The company had customers, including private jet fleet operators NetJets and Flexjet, for its $120 million AS2 aircraft that would fly at Mach 1.4. Aerion was seeking to raise capital for an assembly plant in Florida and had signed on Boeing as a manufacturing partner. That financing fell through, and Aerion abruptly closed in 2021. This failure cast a dark cloud over the industry about the high risk of the supersonic dream.

The risk will be reduced a bit with regulations in place that would allow a supersonic aircraft to take off and land at most airports around the globe. The FAA’s proposal is for a boom that has a maximum pressure release of 0.11 pounds per square foot at ground level, which is much lower than a military jet that produces a boom of about 1 to 10 pounds per square foot.

You can bet that aircraft makers are in early discussions with engine makers about the viability of a supersonic plane that will cost billions of dollars to develop. Planemakers will want exclusivity on the engine, which will be a technological feat that juggles the tradeoffs of speed, noise and fuel consumption. Engine makers will want multiple customers to provide as much volume as possible to recover the development costs and make a profit.

However the race shakes out, it won’t start with an airliner like the Concorde. The industry will have to work up to the boom.