George Monbiot recently coined "perceptionware" — technology trailed but never trialled, designed only to pacify the credulous — in his critique of Heathrow expansion. Guardian reader Robin Hughes of Worrall, South Yorkshire, offers a sharper, older term: "vapourware," borrowed from the IT industry, where it describes products announced to shape market perception but never actually shipped. Applied to aircraft emissions, the fit is uncomfortably precise. The aviation industry has spent two decades announcing breakthrough fuels, hydrogen propulsion, and electric aircraft that remain perpetually five-to-ten years away. Sustainable aviation fuel (SAF) accounts for less than 0.1% of global jet fuel consumption. Hydrogen-powered commercial flight has no certified airframe. Electric aircraft remain confined to sub-20-seat prototypes with range limits that make them irrelevant to the routes generating the vast majority of emissions. The announcements keep coming; the kerosene keeps burning. Hughes's linguistic intervention matters because naming the pattern is the first step to resisting it. "Vapourware" carries decades of accumulated skepticism from an industry that learned the hard way: if a company announces a product to freeze competitors rather than to ship, the product rarely ships. The aviation sector's green technology announcements serve an analogous function — they freeze regulation by promising that the problem is about to solve itself. The Heathrow expansion context sharpens the point. Expanding runway capacity on the promise of future emissions technology is precisely the vapourware play: commit capital to infrastructure that locks in demand, while deferring the environmental cost to technologies that may never arrive at scale. The asymmetry is structural — concrete gets poured now, carbon reductions arrive never. The remaining letters in this Guardian collection are unrelated to aviation — covering London flatsharing etiquette in the 1960s, editorial juxtaposition humour, gendered language, and a helium-balloon sign in Ilkley — but Hughes's letter stands out for the precision of its analogy. It identifies a mechanism, not just a grievance. What makes this small observation analytically potent is that it connects two industries with documented histories of the same pattern. Tech vapourware was eventually disciplined by market accountability — customers stopped believing. Aviation's version faces no equivalent discipline because the customers (passengers) don't make purchasing decisions based on propulsion technology, and the regulators keep accepting the next round of promises. The structural question is whether aviation's vapourware era ends the way tech's did — with a reckoning — or whether the absence of market discipline allows it to persist indefinitely. Twenty years of announcements with sub-0.1% SAF adoption suggests the latter unless regulatory frameworks stop accepting promissory notes as payment.
