Airbus sent shockwaves through the civil aviation world when it said deliveries of its 21st-century flagship, the double-deck A380 superjumbo, would be delayed by up to six months.

The announcement took the gilt off one of the most trumpeted aviation launches in decades and at least one disgruntled airline said it would seek compensation.

Signs that the introduction of the largest passenger plane ever built was not going according to plan emerged last month when Singapore Airlines, which was due to launch the first scheduled A380 service from Heathrow said it had been notified of a postponement.

Delays to new aircraft are not uncommon, but this adds to a growing list of headaches at the European aircraft builder as it slides into a major trade dispute over subsidies with arch-rival Boeing and struggles to fill an internal power vacuum created by its squabbling shareholders.

Keeping the ten billion euro (£6.757 billion) project on track after cost overruns and now delays will be a major task for the next head of Airbus, who has yet to be appointed after its fiery French boss Noel Forgeard fought to become the next co-CEO of parent EADS.

Shares in EADS, which had been on the backfoot since Australian carrier Qantas said delivery of the A380s it has bought would be delayed by six months to April 2007, fell as much as much as 2.2 per cent on yesterday ' s announcement.

Qantas said it planned to seek compensation from Airbus.

"This is disappointing, given that we have met all of Airbus' deadlines for Qantas specifications," chief executive Geoff Dixon said.

"We are developing contingency plans to ensure there is no impact on our schedules or available capacity during the six-month delay."

Emirates is the biggest customer with an order for 43 planes worth over $12 billion ( £ 6.593 billion) and Air France has ten on order.

Airbus confirmed deliveries would be delayed up to six months but said no series flaws in the aircraft had been discovered in test flights.

Industry analysts said it was not clear how much Airbus might have to pay in compensation to airlines for the delay.

Airbus contributes virtually all operating profit at EADS, which owns 80 per cent of the company. The balance is held by Britain's BAE Systems.

Airbus operating margins are benefiting, however, from a rebound in the dollar, the payment currency for aircraft.