The purchase agreement, signed at the Singapore Airshow, put the European manufacturer on track to meet its target of 30 orders for the world's largest passenger plane in 2014.

Airbus had suffered some setbacks last year with the discovery of cracks on some of the giant jetliners' wings.

But John Leahy, its chief operating officer for customers, said: "This firm order from Amedeo is a clear recognition of the A380's long-term market appeal.

"The A380 is the best tool for airlines to capture growth and increase profits."

Amedeo, formerly Doric Lease Corp, is the world's biggest manager of leased A380s.

"As world air traffic continues to double every 15 years and airport infrastructure and slots do not, the A380 is the best solution for airlines to capture that growth," said Amedeo chief executive Mark Lapidus.

The orders will be delivered from 2016 to 2020. Amedeo will announce its engine selection later.

"Put it in the right routes at peak traffic times and it is an unbeatable profit-generating machine for airlines," Lapidus said.

Airbus said more than 120 A380s are now in operation worldwide following its launch in 2007.

Leahy said the company wants about 30 orders for the A380 this year.

Despite the lift for Airbus from the Amedeo deal, one analyst said it should look beyond the A380.

"It's more an exception than the rule because we don't see a huge demand for this aircraft," said Shukor Yusof, with Standard and Poor's Equity Research.

"This is a niche aircraft meant for a small market. Airbus would do much better to focus on the A350," he said, referring to a new generation of long-range aircraft.

Airbus says it has received 814 orders so far from 30 countries for the A350-XWB, a wide-body plane due to begin service with Qatar Airways in the fourth quarter of 2014.

The Amedeo order was the second major deal announced by Airbus at the Singapore trade show.

On Tuesday fledgling carrier VietJetAir ordered 63 Airbus A320 jets with a list price of $6.4 billion in an expansion programme that underscores Asia's central role in the future of world aviation.

The deal also covers rights to acquire or lease 38 more A320s, potentially boosting the budget carrier's current fleet of 11 A320s tenfold.

Another European plane manufacturer, ATR, secured important contracts on Wednesday.

It signed a nearly $500 million deal with leasing firm Dubai Aerospace Enterprise for 20 ATR 72-600 planes.

It also signed a $150 million agreement with Bangkok Airways for six ATR 72-600s, with an option for the Thai carrier to buy two more.

Dubai Aerospace is the biggest aviation leasing firm in the Middle East, with an aircraft portfolio of about $3.3 billion comprising Boeing B737s and B777s, as well as Airbus A320s and A330s.

It has an option to buy 20 more of the ATR aircraft.

In another deal unveiled at the Singapore show, Thai budget carrier Nok Air on Wednesday committed to buy 15 B737s from Boeing worth $1.45 billion.

The commitment is for eight next-generation 737-800s and seven 737 MAX 8s, Nok Air and Boeing said.