Air Berlin has agreed the sale and leaseback of four Airbus A320s with US lessor GECAS.
The aircraft, all fitted with CFM International CFM56 engines, are scheduled for delivery this year.
GECAS has confirmed the agreement. Air Berlin says GECAS is its largest lessor.
Air Berlin disclosed last month that it would sell eight aircraft - mainly Boeing 737s - to a new lessor, Jackson Square, as well as four A320s to a company identified as Lionhart Aviation.