Surely many are familiar with Luc Besson’s film The Fifth Element, in which Bruce Willis, who plays Korben Dallas, searches the endless tall skyscrapers, hauling a car-like air taxi to the daily filler. The forms of transport seen in Franco-British sci-fi were once thought to be the minimum smile of dreams in our lives, but the 24 years since the cinema was shown proved to be a breathtaking tale, responsible dreamers of transport technology take work seriously, at least most.