The testosterone-soaked pilots of Top Gun felt the “need for speed”. So do French and Japanese aviation executives, who Wednesday resurrected plans for supersonic civil aircraft.

The precedents are not encouraging. Developing Concorde cost $30bn. Conceived in an era of $2 a barrel oil, its operating economics proved hopeless.

The Soviet Union's Tu-144, nicknamed Concordski due to its suspiciously familiar design, ended up flying mail between Moscow and Kazakhstan. Nasa abandoned its programme in 1999. Its best case scenario, with demand for 500 aircraft, required $18bn spending upfront. The private sector is capable of funding huge investment: UK water companies will invest $32bn on pipes and sewers over the next five years. But capital intensive technology projects with binary outcomes rarely add up in discounted cash flow models. That is no bad thing. While French and British politicians promoted Concorde and its spiritual successor, Eurotunnel, the private sector revolutionised millions of lives with sub-sonic flights.

Mistakes occur. Shanghai's $1.2bn, 430kph airport train takes eight minutes to get passengers to a terminal that is a 45-minute cab ride from the city centre. However, the message that prestige is not always progress may be getting through. A planned $48bn link between Beijing and Shanghai has been abandoned. That leaves Nasa, with its annual $16bn budget. When it comes to net present value, space is the final frontier.

Copyright The Financial Times Limited 2018. All rights reserved.

Comments have not been enabled for this article.