Airbus unveiled a provisional deal on Friday to sell four A380s worth $1.5 billion at list prices to Transaero Airlines, marking the first sale of Europe's superjumbo to a Russian airline.

The country's second-biggest carrier plans to introduce the double-decker jetliner on long-distance flights seating 700 people in three classes, Airbus said.

It will be the second airline to opt for a high-density layout after France's Air Austral, which has said it will use close to the maximum capacity of 853 seats.

The world's largest airliner, which entered service four years ago, has the capacity to carry 525 passengers in a standard three-class layout.

It was initially branded as a cruiseliner with open areas and space for first-class suites, but a market is also opening up for high-density travel to offset high fuel prices while creating some uncertainty over how this should be marketed.

The passenger is still getting a wider and more comfortable seat than on another plane, an Airbus spokeswoman said.

Airbus said the economy seat on its A380 is 5 cm wider than on a Boeing 747 using similar cabin layouts.

Boeing disputes this and says the latest version of its most recognized aircraft, the 747-8, will use an airy design with softer LED lighting, more spacious bins and a redesigned entry-way comarable to its all-new 787 Dreamliner.

Seat widths on the 747-8 are comparable to the A380, within 2 cm, company spokesman Jim Proulx said.

As well as the A380, Transaero is also considering buying the 747-8, which is due for first delivery in 2012.

We are in deep talks with Boeing about a potential order for the 747-8. The order for A380s is a separate order and does not have an impact on the talks, an airline spokesman said.

The 747-8 Intercontinental will be the world's longest passenger jet and is designed to seat 467 people in a standard three-class layout. Boeing has applied to have the plane certified to seat 605 people in high-density mode.

It has sold 36 of the passenger aircraft with another 15 committed provisionally to an unidentified customer.

Transaero carried 6.65 million passengers last year, 32.3 percent more than in 2009. It has a fleet of 64 aircraft, almost all of them Boeing.

It will now be considered the launch customer for the A380 in Russia, the CIS and eastern Europe, Airbus said.

Its Domodedovo base outside Moscow is the only Russian airport currently capable of handling the huge plane.

Airbus believes traffic in the region will increase at an average rate of 5.6 per cent per year over the next 20 years.

Transaero will announce its choice of engines for the A380s in the near future, Airbus said. The two rival suppliers are Rolls-Royce and Engine Alliance, a joint venture between General Electric and Pratt & Whitney .

Airbus has sold a total of 236 A380s worldwide.

Industry sources said last month it would sell another 5 aircraft to Qatar Airways, doubling that airline's A380 order, at the Dubai Air Show next month, when the same airline would also opt for Engine Alliance engines.

(Editing by David Holmes, Greg Mahlich)