LONDON (Reuters) - European planemaker Airbus (>> Airbus Group) unveiled a new cabin brand on Wednesday designed to help cost-conscious airlines carry more passengers on long-haul flights while avoiding additional discomfort.

The move reflects the rivalry between major planemakers to jazz up interiors and give airlines more flexibility on cabins as the industry struggles to capture more traffic without angering passengers.

Airbus said the "Airspace by Airbus" brand would debut on its upgraded A330, the A330neo, which is due in service from late 2017, before the new designs are rolled out to other jets.

Airlines will still be able to choose what cabin layout they want but with the new designs an A330neo will on average gain 10 seats compared with the existing A330 model, which can take up to 300 passengers.

Airbus and rival Boeing (>> Boeing Co) are vying to add more seats to make their jets more economically attractive for airlines while claiming passengers will not feel the difference, though many consumer groups say cabins feel increasingly crowded.

The trend has produced increasingly bitter industry branding wars in recent years, with each of the world's two largest planemakers accusing the other of sacrificing comfort.

Airbus said by rearranging galley and lavatory space, the extra seats would be added to the A330neo with no reduction in seat width and still with eight seats across each row.

"We are putting more passengers on the same amount of space but because of the cleverness and the way we have designed it we don't have to compromise on comfort," Airbus's executive vice president of strategy and marketing Kiran Rao said.

The same set of options will later be available on the long-haul A350 and A380, adding 12 seats and 50 seats respectively, Airbus said.

Adding seats is one way to reduce operating costs per seat, a key industry barometer, alongside changes to the structure of the aircraft itself or more efficient engines.

At the same time, planemakers are increasingly stepping into areas previously jealously guarded by airlines and specialist cabin suppliers by offering eye-catching effects, competing more on cabin experience rather than launching costly new models.

Boeing has a cabin brand called Sky Interiors and recently unveiled projections of light and images on ceilings and walls.

Airbus said its new brand would include a quieter cabin and new ambient lighting options as it tries to address the growing importance of cabins on social media, where passengers post reviews and photos, and make decisions based on them.

Analysts also said a standardized palette of cabin options could help to reduce the delays which have plagued the plane cabin industry and threatened some deliveries as airlines demand more and more customized features.

Fabrice Bregier, president of planemaking at Airbus has said French seatmaker Zodiac (>> ZODIAC AEROSPACE), which has been dogged by production delays, would not be involved with the A330neo.

(Additional reporting by Tim Hepher; editing by David Clarke)

By Sarah Young

Stocks treated in this article : Airbus Group, ZODIAC AEROSPACE, Boeing Co