It will take a week to board everyone

But it is projected to be cheaper to fly.  At right is a diagram (click to enlarge) of the world's largest passenger aircraft, the Airbus 380.

Hailed as a "European success story" by the European Union, the massive plane can seat up to 840 passengers on its two full decks, and its size easily eclipses the Boeing 747 that has ruled the commercial skies for decades.

Four countries -- France, Spain, Germany and England -- invested heavily in the $13 billion, 10-year effort.  The first test flight will be in March of this year and the first commercial flight in March of 2006, when Singapore Airlines expects to put the plane into service.

Airbus already has firm orders for 149 planes at a list price of about $275 million.  The project went about $1.5 billion over budget but is still projected to be profitable.

With the three-tier seating (economy, business and first classes), the plane will hold about 555 passengers.  Other possibilities may include the installation of gyms, bedrooms, lounges or recreation areas.