Delta Air Lines has confirmed that it has placed an order for 100 Boeing 737-900ERs to replace its older aircraft.
The aircraft are scheduled for delivery between 2013 and 2018.
The order will enable Delta to replace "on a capacity-neutral basis older technology aircraft that will be retired from the fleet", said the carrier.
Delta will take delivery of 12 737-900ERs in the second half of 2013. A further 19 aircraft a year will be delivered between 2014 and 2017, and the remaining 12 aircraft will join its fleet in 2018.
The aircraft, which will feature Boeing's Sky Interior, will be equipped with CFM International CFM56-7B engines.