By Monitor l THE news from the Paris Air Show that Japan and France are to collaborate on a supersonic airliner that would carry 400 passengers non-stop between New York and Tokyo in seven or eight hours will have brought a heady air of unreality to the hard-driven reality of selling aircraft that are already in existence or close to being taken off the drawing board. It would be surprising if France were to get involved in another fantasy aircraft such as Concorde, but it could happen. Certainly those with experience of the only existing 16 hour non-stop between New York and Tokyo on the adapted Boeing 747 will wish them well. In the meantime, the looming battle between Europe's Airbus A380 and the US's Boeing 787 drew closer during the Paris show. Airbus is trying to take air travel into a new dimension with its huge passenger capacity while Boeing is backing its belief that smaller but more flexible aircraft such as the 787 will the winner in the future. There are signs that airline orders are beginning to prove Boeing right and Airbus' decision to produce also a smaller A350 as a rival to the 787 suggests that it has recognised this fact. Boeing believes that about ten per cent of aircraft sold in the next 20 years will be of its 787 type but only three per cent will of the A350 model carrying more than 400 passengers. A year or so ago it seemed that Airbus had taken a decisive lead over Boeing in the global aircraft market. The American manufacturer had experienced several technical and managerial setbacks while Airbus' progress with the A380 seemed impressive. Now the scene has changed: Boeing has regained its confidence and succeeded in suggesting that Airbus may have misread the market for its huge new plane; at the same time Airbus has had to admit to a delay in delivering the first A380s to Singapore Airlines. Everything is still to play for but Boeing now seems to have the edge.