Passengers on short-haul flights with British Airways will no longer be able to recline their seats.
A new fleet of aircraft based at Heathrow will be installed with the non-reclining seats.
The 35 A320neo and A321neo planes, coming into use from this year, will instead have a fixed "gentle recline".
It is a move already adopted by budget airlines, with easyJet and Ryanair already using seats that cannot be adjusted.
The move comes after the airline reduced its in-flight meals offering on its short-haul flights for economy passengers.
It now offers paid-for snacks from Marks & Spencer.
The airline is adding an extra seat into economy class rows on some of its long-haul aircraft from this summer to enable it to offer "even more low fares".
The Gatwick-based Boeing 777s will have 10 seats on each row rather than the current configuration of nine.
This will bring BA into line with airlines including Emirates and Air New Zealand.
The carrier also announced a shake-up of its catering for economy passengers on long-haul flights.
This will include a four-course meal replacing the existing three-course offering, and the introduction of Magnum ice cream and Graze snack boxes.