EasyJet will test giving passengers a pre-arranged seat on several routes from next spring.
It could end the free for all, as passengers who have not paid to reserve seats vie for the best spot, or families attempt to get spaces beside each other. EasyJet will still allow passengers to pay for pre-booking popular seats, such as those with extra leg room.
No frills airlines have traditionally dispensed with seat allocation to cut costs and encourage passengers to board quickly.
However, chief executive Carolyn McCall said the easyJet experiment would be abandoned if it caused delays. She declined to say if Scottish routes would be included in the trial.
She said: “If it increases boarding time, we will not do it.”
Ms McCall also said it had still to be decided how passengers would be boarded. She said: “We will be looking for answers as to how best to board in the most efficient, simple way.”
Some experts have claimed boarding by seat rows is inefficient, and getting passengers on to a plane in a more precise order – so they are not trying to get to adjacent seats at the same time – would be quicker.