In 1969, a British Airways Concorde crossed the Atlantic at Mach 2.04. Passengers sipped champagne at 60,000 feet while the curvature of the Earth was visible through their windows. London to New York took three and a half hours. That was 57 years ago. Today, the same flight takes seven hours. The plane is slower. The cabin is wider. The champagne is extra.

Commercial aviation has done something almost no other technology has: it went backwards. Cars are faster. Computers are faster. Communications are faster. Passenger aircraft are slower than they were during the Johnson administration. This is not an accident. It is a choice — and the reasons behind it reveal everything about how aviation actually works.

The Concorde Paradox

Concorde was a technological triumph. It was also an economic disaster. The aircraft burned roughly 25,000 litres of fuel per hour — about four times what a Boeing 747 consumed while carrying four times fewer passengers. The fuel cost per seat-mile was catastrophic. Only 20 Concordes were ever built, and British Airways and Air France operated them at a loss for most of their lives.

The sonic boom made it worse. Concorde’s shock wave rattled windows and spooked livestock across a miles-wide corridor. The United States banned supersonic flight over land in 1973, restricting Concorde to oceanic routes. The aircraft could only fly fast where nobody lived — which meant it could only serve a handful of city pairs. London–New York. Paris–New York. London–Barbados. The route network was tiny.

When Air France Flight 4590 crashed on takeoff from Paris in July 2000, killing 113 people, the fleet was grounded for over a year. The September 11 attacks in 2001 collapsed premium transatlantic demand. By 2003, Concorde was retired. The supersonic age ended not with a whimper but with a spreadsheet.

Why Subsonic Won

The real revolution in commercial aviation was not speed — it was efficiency. The Boeing 747, introduced in 1970, could carry 400 passengers at Mach 0.85. The Airbus A380, launched in 2007, carried 550. Modern twin-engine wide-bodies like the 787 Dreamliner and A350 burn 20% less fuel per seat than aircraft from the 1990s. Airlines discovered that passengers cared far more about ticket price than flight time.

The economics are stark. Drag increases roughly with the square of speed in subsonic flight — but at transonic and supersonic speeds, wave drag creates an exponential penalty. Flying at Mach 2 requires roughly four to five times more fuel per passenger-mile than flying at Mach 0.85. The physics are non-negotiable.

Modern airliners cruise at Mach 0.78–0.85, in a narrow speed band where fuel efficiency is optimised. Some — notably the Boeing 787 — actually cruise slightly slower than the 707 did in 1958, because the fuel savings from a few knots slower translate into millions of dollars per year across a fleet. Speed was traded for economy. The airlines chose cheap seats over fast arrivals, and passengers voted with their wallets.

The Supersonic Revival

The dream has not died. Boom Supersonic, a Denver-based startup, is developing the Overture — a Mach 1.7 airliner designed to carry 65–80 passengers on transoceanic routes. The company has orders from United Airlines, American Airlines, and Japan Airlines. Its XB-1 demonstrator has flown. The target date for Overture’s entry into service is 2029.

Boom’s pitch is different from Concorde’s. The Overture is designed around modern turbofan engines burning sustainable aviation fuel. It is not trying to be Mach 2 — it is targeting Mach 1.7, which reduces the thermal and structural challenges significantly. It will be quieter. It will be more fuel-efficient per seat than Concorde by a wide margin. And it will still face the sonic boom ban over land, limiting it to ocean-crossing routes.

NASA is working the other angle. Its X-59 Quesst aircraft is designed to reduce the sonic boom to a “sonic thump” — a gentle rumble instead of a window-shaking crack. If the X-59 proves that low-boom supersonic flight is tolerable over populated areas, the FAA may lift the overland ban. That would transform the economics of supersonic travel overnight, opening up thousands of domestic and continental routes.

Faster Is Coming — But Not for Everyone

The honest answer to “why don’t planes fly faster?” is that most people do not want to pay for speed. They want cheap flights. They want wide seats. They want Wi-Fi and lie-flat beds. A seven-hour transatlantic crossing with a movie and a meal is acceptable to most travellers. A three-hour crossing at twice the ticket price is a luxury product.

Supersonic will return. It will serve the routes and passengers willing to pay the premium — just as Concorde did. But the age of every airliner being supersonic, the future imagined in the 1960s, is not coming. The laws of physics and the laws of economics agree on one thing: for most of aviation, Mach 0.85 is fast enough.

Concorde proved humans could fly at twice the speed of sound in shirtsleeves. The question was never whether it was possible. The question was whether it was worth it. For 27 glorious years, the answer was yes — as long as someone else was paying.

Sources: British Airways Concorde Heritage, NASA Quesst Programme, Boom Supersonic, Smithsonian National Air and Space Museum, Aviation Week