Pegasus Airlines has placed a firm order for 75 Airbus A320-family neos, with options for a further 25 units.
The Turkish carrier signed for 58 A320neos and 17 A321neos at a press conference in Istanbul on 18 December. The aircraft have a list value of $12 billion.
"It is with great pride that we are placing the biggest order in the history of Turkish civil aviation with Airbus for up to 100 A320neo family aircraft," said Pegasus chairman Ali Sabanci.
The A320neos will be configured with 180 seats, while the A321neos will have a 220-seat configuration.
Christopher Buckley, Airbus executive vice-president Europe and Asia-Pacific, said negotiations between the two parties took more than 10 years, with the 100-aircraft deal marking the third attempt at finalising a contract.
Pegasus currently operates a fleet of 37 Boeing 737-800s and two 737-400s, according to Flightglobal's Ascend Online database.