Professor Martin Lowson is jet-lagged. Just a few hours ago he was on a transatlantic flight from the Rockies, where he's been walking with his wife. "I've only just got out of bed, actually," he grins, looking down at his open-necked shirt. "Maybe I should have worn my suit. But, well, the captains of industry I meet ... Ha! They never wear suits!"
Lowson is all smiles when we meet, but takes on a more serious air when we move from small talk to science. He's spent pretty much all of his working life in aeronautics, designing planes, helicopters - and spaceships.
He worked on Nasa's lunar landing programme, but rather modestly says that his memories of putting men on the moon "might not make much of a story". He never saw the project as anything particularly life-affirming, he says: "If the Americans wanted to pay me all this money to do this work, then I was going to do it. I never realised its significance. It was only when everyone started making a song and dance about it that I thought: 'My word!'"
What working in the US did do, he says, was stimulate his mind. When he eventually returned to England to take a job at Rolls Royce's aeronautics division, he often found himself longing for the American can-do attitude.
"I came back to Britain because I wanted to bring my kids up as English rather than American," he says, "but I found the UK a bit dull. In America, people would say: 'If we can put a man on the moon, we sure as hell can do this.' Here, people would always say: 'Oh no, we can't do that.' I had to go back to the US every six months for a recharge."
Certainly, Lowson has been successful in the UK - he holds the patent for the rotor-blade used on the Lynx, which has held the helicopter speed record since 1986 - but finally he became sick of the inertia he found in UK engineering. "I came to the conclusion that people weren't interested in research and ideas," he says.
"They were only interested in routine developments. They'd ask me: 'Can we increase this by one per cent?' If we came up with anything that was a major step forward, they didn't want to know."
Today, Lowson continues to use his knowledge of aeronautics and aerodynamics, but rather than designing aircraft for large companies he's established a business to work on a "£1,000 billion idea" which he kept to himself for more than 20 years: a solution to the regeneration conundrum of rapid urban transit. He says his company, Advanced Transport Systems Ltd, is close to agreeing a deal to bring a network of Urban Light Transit (Ultra) 'taxi' pods to Heathrow airport. Lowson claims that these lightweight pods, which can collect or drop up to four passengers at any point along their dedicated track, are up to three times more energy-efficient and cheap to run than trams.
If Heathrow takes the plunge, Medway Council has already said that it is interested in following the airport's lead, he says. "We have a long line of local authorities who are desperate to be second!" he adds.
In recent years, many cities have plumped for trams as a way of connecting people and jobs, but plans to build tramways in Liverpool and Leeds, and to extend Manchester's network, have been reined in by the Department for Transport. In this struggle between local and central government, Lowson sides with the department. "Trams were widespread in the 1910s and 1920s," he says, "but they were taken out of service because they no longer met the needs of the community. The new tram schemes are being driven by nostalgia rather than genuine analysis. You cannot provide a tram system cost-effectively; they require really big subsidies." Trams might not pollute city centres, he adds, but they require far more energy to run than their proponents claim. "Light rail is nowhere near as efficient as it's put out to be."
Like most scientists, Lowson cannot abide claims based on faith, emotion, bogus mathematics or amateurish research. He considers himself a system engineer rather than an inventor. He says: "An invention is like a spark that appears in the night. Well, those sparks are usually wrong. We get to an idea by working through a problem in a new way." Indeed, he gets angry about what he sees are untruths which skew the debate about trams' efficiency.
Lowson prefers to stick to the evidence - even when his unfashionable conclusions risk stirring controversy. In engineering "there were never many women," he says. "It's probably because women are less likely to make good engineers. That's not to say that individual women can't make excellent engineers - of course they can. But in general ... well, there's a huge body of evidence on this. Most studies show that men are more likely to have an affinity with things, while women are more likely to have an affinity with people. Yet for some reason we often choose to ignore the evidence."
Lowson is banking on what he says is robust evidence to make the case for Ultra. So if, in a few years, Ultra pods are zipping around Heathrow and Medway - perhaps even his home town of Bristol - will he feel vindicated? "Yes, you do feel a sense of satisfaction," he says, "though you always know it's not really yours; it's a team effort. But obviously it's nice to have ideas that change things. That's why I came into engineering: to solve problems."
1955: Becomes engineering apprentice with Vickers Armstrong.
1963: Graduates with a PhD from Southampton and joins Wyle Laboratories as head of applied physics.
1973: Joins helicopter manufacturer Westland as chief scientist, then director of corporate development.
1986: Made professor of aerospace engineering at Bristol University.
2001: Appointed professor of advanced transport at Bristol University.