EasyJet is rolling out allocated seating across its network in November, having completed a successful trial of the scheme on more than 6,000 flights.
The low-cost carrier's passengers will now be allocated seat numbers prior to boarding, and must pay fees for switching to alternative seats.
Front-row and over-wing seats will be charged at £12 ($19); the first four rows behind the front row will cost £8; and any other location costs £3.
Commenting on the trial, EasyJet chief executive Carolyn McCall says: "The majority of passengers were simply allocated seats when they checked in.
"Some passengers chose particular seats, with best-selling seats usually those near the front, for those who wish to get off the aircraft quickly at their destinations, and exit row seats with their extra legroom."
Allocated seating will be introduced on 13 November at Gatwick South, Luton, Stansted, Southend, Bristol and Glasgow airports.
On 20 November it will be expanded to Gatwick North, Milan Malpensa, Rome Fiumicino and Paris Charles de Gaulle airports. All of EasyJet's remaining bases will introduce the service on 27 November.