Airbus unveiled the world's biggest passenger jet in a glitzy ceremony in which the leaders of France, Britain, Germany and Spain hailed Europe's victory over the United States as the new king of the commercial skies.The huge A380 superjumbo, which can carry up to 840 people on its two full decks, supersedes the ageing 747 by US rival Boeing as the biggest civilian aircraft ever made.When it is put into service early next year, it will become the flagship of many airline fleets and offer unprecedented amenities on long-haul services, including, in some cases, gyms, bedrooms and bars.For the countries...