Irish and US aircraft leasing business GECAS has placed an order for 40 Boeing 737s with a list price of nearly $4bn (€3bn).
GECAS (GE Capital Aviation Services) said it placed an order for 20 Boeing 737 Max 8s and 20 next generation 737-800s.
The order comes as Taoiseach Enda Kenny prepares to address a major annual international air finance conference in Dublin this morning. The event, held annually in the capital, draws senior aviation executives from all over the world.
Norman Liu, president and chief executive of GECAS, said the company had ordered more of the aircraft because demand continued to grow and airline customers were also requiring more fuel-efficient aircraft to compete in the marketplace.
"This order further strengthens the large GECAS order book," he said.
It brings the number of 737 Max Boeing aircraft ordered by GECAS to 95 and the number of 737 next generation aircraft it has on order to 387. GECAS is the world's largest aircraft leasing firm.
GECAS is part of General Electric, which also makes jet engines for the 737 as part of a joint venture.
Formed after GE bought the bulk of Tony Ryan's collapsed Guinness Peat Aviation (GPA) in 1993, GECAS manages most of the 1,700 aircraft it has on its books out of Ireland.
In the last 20 years, Ireland has emerged as one of the world's top aviation finance and aircraft leasing bases.
Before Christmas, leasing firm AerCap said it was paying $5bn to buy US rival International Lease Finance Corporation (ILFC).
AerCap, which is listed on the New York Stock Exchange, has a fleet of 378 aircraft worth $15bn on its books. It manages the aircraft out of Shannon, while it has its corporate HQ in the Netherlands.
Headed by chief executive Aengus Kelly, AerCap bought the smaller part of GPA that had not been acquired by GE.
The deal to buy ILFC, which is due to close in May, will make AerCap the world's second biggest aircraft leasing firm after GECAS.
AerCap will probably have a market capitalisation of around $8bn after the ILFC transaction is complete. ILFC is wholly-owned by insurer AIG.
There are a number of other major aircraft leasing firms in Ireland, including SMBC Aviation Capital, headed by former GPA employee Peter Barrett.
Another former GPA worker, Domhnal Slattery, made his first fortune by selling a Dublin-based aircraft financing business to Royal Bank of Scotland in 2001 for about £30m (€45m at the time).
He went on to found privately owned aircraft leasing firm Avolon, also based in Dublin. It has 182 aircraft on its books.
Another firm, New York-listed Fly Leasing, is also based in Dublin. It is headed by chief executive Colm Barrington, who's also the chairman of Aer Lingus.
Mr Kelly has predicted a number of stock market listings in the leasing industry.
This week, the Irish Stock Exchange also said it was launching a dedicated exchange for aviation debt listings.
There are already 26 aviation-related debt instruments listed on ISE markets, with a total value of $12.7bn.