Qantas Airways Ltd. and AirAsia Bhd. are challenging Singapore Airlines Ltd. and other full-service carriers with a low-fare, long-haul business model that has previously failed.

Qantas’s Jetstar unit will add budget long-haul flights from Singapore later this year. The carrier cuts costs by renting movies to passengers and using lightweight equipment to pare fuel usage. AirAsia X, which flew more than 1 million passengers in 2009, squeezes 35 percent more seats onto its planes than full-service carriers to pare expenses.

The two carriers also have support from existing airlines, with AirAsia X able to access flights to about 70 cities from its Kuala Lumpur hub through cooperation with AirAsia Bhd., Asia’s largest budget carrier. These ties may help the long-haul carriers avoid the fate of standalones Oasis Hong Kong Airlines Ltd. and London-based Zoom Airlines, which both folded in 2008.

“Long haul, low cost is transforming the whole aviation landscape in Asia,” said K. Ajith, an analyst at UOB-Kay Hian Research in Singapore. “Budget carriers may be a force to reckon with in the future because if they have a strong network and are viable, they can potentially lure passengers from established carriers.”

Long-haul discount airlines differ from Southwest Airlines Co. and Ryanair Holdings Plc because they offer flights of more than five hours and have premium-class seats. AirAsia X, part- owned by AirAsia Bhd., flies twin-aisle Airbus SAS planes to London and Australia, and it’s planning services to Japan and South Korea. Jetstar intends to begin Singapore-Melbourne flights in December followed by services to Auckland in March. It’s also planning flights to European and Asian destinations.

“There seems to be a market for long-haul discount travel if prices are low enough,” said Sean Fenton, who helps manage $740 million at Tribeca Investment Partners in Sydney. “It’s a threat to the incumbent carriers.”

AirAsia X charges from about 1,286 ringgit ($400) for a flight from Kuala Lumpur to Stansted Airport, 40 miles outside of central London. An economy ticket on Malaysian Airline System Bhd., the nation’s largest carrier, to Heathrow Airport costs from about 2,104 ringgit. Singapore Airlines charges from about S$1,486 ($1,067) for a Singapore-Heathrow coach-class ticket.

Singapore Airlines serves “different market segments with different service propositions,” Nicholas Ionides, a spokesman, said in an e-mail reply to Bloomberg questions. (Bloomberg)