Lightweight new seats are being installed across the easyJet fleet by the end of next summer.
Ergonomically designed, they have been installed on the first of 14 aircraft with the remainder due for deliver over the next year and a half.
The budget carrier claims the new seat will improve fuel efficiency and reduce CO2 emissions.
The airline is also introducing lightweight trolleys onboard as well as aerodynamic improvements such as sharklets, an enlarged wing tip which makes the wing more efficient.
The look of the cabin has also been redesigned to create a more modern feel.
The backrest of the new seat is at a 15 degree angle for a relaxed seating position and the slimmer backrest provides more space for passengers, according to easyJet.
Marketing director Peter Duffy said: “It has been ergonomically designed with the comfort of the passenger top of mind so the backrest angle is pre-defined for a relaxed sitting position and the seat is designed to provide more space for passengers.
“EasyJet’s new seat selection also has the passengers’ wallets in mind – the lighter weight brings fuel savings which in turn enables us to continue to maintain our low fares – even when fuel prices remain at historic highs.”