Since 11 September, the global airline business has been in flux, with wobbly passenger confidence and over-capacity on long-haul routes as no-frills outfits like Easyjet and Ryanair clip the wings of the big national carriers. The planes will be changing too. Even before that fateful day, manufacturers were busy deciding on the shape of thing to come. That depends on which of the two dominant players you believe - Boeing in the US or Airbus in Europe.
THE CHALLENGE: The number of airline passengers has quadrupled since 1970 (to 1.6 billion a year), but airliners haven't changed much. Barring the elegant financial and technical cul-de-sac that is Concorde, the last big leap forward in commercial aircraft was the Boeing 747, which first flew in 1969 and is still going strong.
Developments have centred on economics, with competing manufacturers winning orders on purchase price or lifetime running costs. Despite predictions that by the year 2000 we'd be flying London to Sydney in three hours on Hotol (a superfast spaceplane of the mid-80s that never got off the drawing board), modern aircraft are neither faster nor much more comfortable than their forebears.
THE SOLUTION: Boeing's contribution to the skies of tomorrow is the Sonic Cruiser. In a remarkable about-face, the company that brought us the Jumbo jet has decided that the days of large aircraft are numbered - the Sonic Cruiser will be small but swift. Seating a modest 200-250 passengers, it will knock an hour or so off current transatlantic times, and a range of up to 18,000km minimises refuelling stops. Flying at Mach 0.95, this airborne greyhound will sniff at the sound barrier but not break it. The economics of supersonic air travel - specifically, the prodigious quantity of fuel required - just don't add up. But you'll have to be patient. The Sonic Cruiser's maiden flight is unlikely to happen before 2008.
Arch-rival Airbus believes that bigger is better, bullishly predicting a market for 1,300 very large aircraft by 2018, and it aims to capture the lion's share. When its double-decker A380 superjumbo enters service in 2006, it will take the 747's laurels as the largest airliner in the world, carrying 550 passengers up to 15,000km non-stop. By contrast, the biggest 747 available carries 400 (a 500-seater is in the offing) and has a range of about 13,000km.
Top-deck passengers on the A380 will be treated to a bar, shops and private sleeping compartments - for a premium fare, of course. With a speed of only Mach 0.89, it's a sluggard compared to the Sonic Cruiser, but you can order one today for a competitive pounds 150 million, and Airbus already has seven customers for 85 aircraft on its books. Watch out Seattle, the Europeans are coming.