The owner of Jet2 and Jet2Holidays is to acquire 27 new aircraft worth $2.6 billion.
The Boeing 737-800s are due to enter service between September 2016 and April 2018.
The order by Dart Group comes as it looks to expand its leisure travel interests as well as renew its airline fleet.
Chairman and chief executive, Philip Meeson, revealed the deal ahead of the company’s annual general meeting later today.
“The board is also pleased to announce that, in order to meet the future anticipated growth of its leisure travel business and for planned fleet replacement, the company has entered into an agreement with Boeing to purchase 27 new Boeing 737-800NG aircraft.
“These aircraft will be delivered between September 2016 and April 2018.
“At current list prices, the total value of this transaction is approximately $2.6 billion, though the company has negotiated significant discounts from the list price.
“The aircraft are expected to be funded through a combination of internal resources and debt.”
He described trading for this summer as being “strong” following a good start to the financial year.
Meeson said: “Demand for our package holiday products continues to grow and as a result the number of package holiday customers as a proportion of overall flown customer numbers has increased.
“The business has also achieved higher airline ticket yields and load factors than in summer 2014. This performance is against a backdrop of slightly lower seat capacity.
“Early indications for winter 15/16 leisure travel bookings are satisfactory.
“In view of the continued strong demand for our leisure travel package holiday and flight-only products, the board is optimistic that group performance for the financial year ending 31 March 2016 will materially exceed current market expectations.”
The company is due to issue a further trading update in mid-October following the half-year end.