Sydney, Oct.25 : THE world's largest passenger jumbo jet, the Airbus A380, is on its way to Sydney as it completes the final leg of its inaugural commercial flight.

Singapore Airlines flight SQ 380 left Singapore at 10.16am AEST and is expected to arrive at Sydney Airport about 5.30pm AEST, although thunderstorms and bad weather could delay the arrival.

The aircraft will return to Singapore on Friday, news.com.au reported.

The take-off was watched by hundreds of airport staff and passengers who gathered in the airport lounge with their pocket cameras and camera phones.

Singapore Airlines chief Choo Choon Seng in a pre-flight ceremony at Changi airport officially launched the giant aircraft today.

"This is a new milestone in the timeline of aviation," he said.

Passengers aboard the flight include 38-year-old Sydney resident Julian Hayward who paid 100,000 American dollarsfor a first class seat and American Thomas Lee, who was also aboard the inaugural Boeing 747 flight in 1970.

Ernest Graaff, another A380 passenger, paid 44,000 dollars for two business-class tickets on the jet.

"I'm excited about being a part of history," he said.

Austrian Georg Burdicek paid 625 dollars for his economy seat, the cheapest one sold during the auction, The Straits Times reported.

Airbus' new aircraft - which boasts two passenger decks and, in Singapore Airlines' version, first-class suites with proper beds - suffered two years of delays caused by wiring glitches, which pushed the plane maker into a loss and led to 10,000 lost jobs.

The production problems and subsequent delay embarrassed Airbus, a bitter rival of US firm Boeing, and some analysts have warned that the gigantic aircraft – which can fit 72 cars on each wing – is a "white elephant".

But others say the behemoth, which can haul 853 passengers in all-economy mode, is about to revolutionise the aviation industry.

SIA's version has 399 economy seats, 60 business seats, and a "suites" class of 12 compartments with flat-screen televisions about the size of a briefcase, sheets by French designer Givenchy and a full-length bed behind sliding doors.

After today's inaugural flight, a regular service between Singapore and Sydney will begin on Sunday.

Superjumbo service on the Singapore-London route would start in February, and Japan could come later, according to SIA executives. (ANI)