Turkey’s Pegasus Airlines is to buy at least 75 Airbus A 320 and A321 medium-haul planes.
The Istanbul-based budget carrier also has options for a further 25 aircraft.
Deliveries will start in 2015 and all will be used on routes in Europe and the Middle East.
Pegasus currently operates Boeing planes and switched allegiance after Airbus reportedly offered bigger price concessions.
However, even with that late-year order, Airbus significantly trails its US rival in sales.
It is the latest round in what has, over the past year, become the fiercest worldwide contest for market share between the two planemakers in a decade.
This order brings Airbus’ total to 721 while Boeing has 1,068.
This week the US company said that based on that strong demand and backlogs of orders it will raise its dividend to shareholders by 10 percent next March.
It also plans to resume the repurchasing of its share that it suspended three years ago, spending up to 1.5 billion euros on that next year.