It flew. That is the strangest, most expensive part of the whole story. The Mitsubishi SpaceJet was not a paper aeroplane or a CGI fantasy that died on a designer's screen. It rolled out, it taxied, it rotated off the runway at Nagoya, and it climbed into a clear Japanese sky in front of cheering engineers. Over the years it logged more than 3,900 hours of flight testing. It was, by most accounts, a rather good little jet.

And then Japan cancelled it. Not because it crashed, not because it couldn't fly, but for reasons that were, in the end, far more mundane and far more humiliating: paperwork, a heavier-than-expected airframe, and a single contract clause buried in American pilot agreements. By the time Mitsubishi Heavy Industries finally pulled the plug in February 2023, the program had consumed something close to ¥1 trillion — roughly US$9 billion — without ever carrying a single paying passenger.

A nation's comeback jet

To understand the heartbreak, you have to understand the ambition. Japan had not built its own commercial airliner since the propeller-driven NAMC YS-11 of the 1960s. When Mitsubishi Heavy Industries officially launched the Mitsubishi Regional Jet — the MRJ — on 28 March 2008, it was meant to be a national homecoming. The launch order came from All Nippon Airways: 25 aircraft, a vote of confidence from the country's flag carrier.

The pitch was genuinely smart. A clean-sheet 70-to-90-seat regional jet with Pratt & Whitney's new geared turbofan engines, promising big fuel savings over the ageing regional jets that ferry passengers between secondary cities all over the world. Entry into service was pencilled in for 2013. Japan Inc. was going to break the Embraer–Bombardier duopoly. What could possibly go wrong?

The Mitsubishi MRJ takes to the air for the first time, 11 November 2015.

Death by a thousand delays

Almost everything, it turned out — slowly. The 2013 target slipped. Then it slipped again. And again. The final design was frozen late, first flight crept from 2012 to 2015, and deliveries marched ever further into the future. By the time the program was done, it had endured at least six major schedule revisions, each one chewing through cash and credibility.

The MRJ finally flew on 11 November 2015, a genuinely triumphant moment. But behind the celebration, the certification process was turning into a quagmire. Mitsubishi's engineers were brilliant at building aeroplanes and badly inexperienced at the labyrinth of proving one safe to the satisfaction of regulators. Crucial parts of the design had to be reworked mid-stream.

The clause that killed it

Then came the problem no amount of Japanese engineering could fix. In the United States — the single biggest regional-jet market on Earth — major airlines' pilot contracts contain something called a "scope clause." It limits the regional jets that feed into the network: typically no more than 76 seats, and crucially, a maximum take-off weight of around 86,000 lbs. It is the law of the land not because of physics, but because of labour politics.

The MRJ90 — rebranded the SpaceJet M90 when Mitsubishi gave the program a glossy new name in June 2019 — tipped the scales well above that weight limit and seated up to 88. Far too heavy, far too many seats. American regional carriers had hundreds of conditional orders on the books, but every one of them was contingent on the unions relaxing scope. The unions made it abundantly clear they would do no such thing.

Mitsubishi did design a fix: the smaller SpaceJet M100, a redesigned 76-seat aircraft engineered specifically to slip under the scope-clause weight limit. But it was a paper escape route, never firmed into hard orders, because by then the whole world could see the program wobbling.

A trillion yen, quietly written off

The numbers had become terrifying. By the end, total program spending climbed toward ¥1 trillion. Mitsubishi Heavy Industries' other divisions were under pressure, a new CEO was determined to stop the bleeding, and the regional-jet dream was looking less like a national triumph and more like a national money pit.

In January 2020 the Western executives recruited to rescue the program were eased out. Then COVID-19 arrived. In October 2020 the program was officially frozen, US operations shuttered, the budget slashed. For more than two years Mitsubishi insisted the program was merely "paused" — a careful, face-saving fiction. Finally, on 7 February 2023, the company stopped pretending and confirmed the SpaceJet was dead.

A deep dive into why the SpaceJet collapsed — scope clauses, certification, and corporate culture.

The most beautiful failure in the sky

What makes the SpaceJet such an unsettling story is that it was not really a failure of engineering. The jets are real. They are sitting in hangars in Japan right now, red-and-white test machines that flew thousands of hours and proved the aeroplane worked. The failure was everything around the metal: an underestimation of how brutally hard it is to certify an airliner, a corporate culture that chased perfection when "good enough, on time" would have won, and a bet that American pilots' unions would blink. They never did.

Japan's once-in-a-lifetime chance to join the global airliner club is, for now, gone. The SpaceJet remains the rarest of aviation artefacts: a jet that flew, dazzled, cost a fortune, and never once carried a passenger who paid for a seat.

Sources: Mitsubishi Heavy Industries (discontinuation notice, 7 Feb 2023); Leeham News; AeroTime; AirInsight; Wikipedia.