Singapore Airlines shops for world's longest jet

Boeing and Airbus are holding a paper airplane contest. A very expensive one. And the winner may get the chance to build the world's longest jet.

The U.S. and European aerospace giants are vying for a coveted spot in the fleet of Singapore Airlines.

By the end of the year, the airline is expected to back one of the company's designs, according to three people familiar with the campaign.

There's a "pretty fierce campaign for this" order from Singapore, said one of the people.

At the moment, the Boeing (BA) and Airbus planes exist largely as PowerPoint presentations that are being evaluated by engineers at Singapore Airlines.

Both planes would be the longest twin-aisle jets ever built and the biggest with just two engines. Nose to tail, they'll be nearly the length of a football field.

Airbus' A350-2000 would be nearly 258 feet long and seat 400 passengers. Boeing's 777-10X would be 263 feet and hold 450, in standard arrangements. That's about 30 and 50 passengers more, respectively, than the current largest A350 and 777X jets.

While both jets may earn the title of world's longest, they won't carry the most passengers. The four-engine Airbus A380 has the distinction of being able to hold more passengers than any other airliner, carrying about 550 people on two decks.

Boeing's new design would put it within striking distance of the A380 and even its own iconic 747 jumbo jet. Both have suffered from slow sales and declining production.