Which airlines offer transferable flight tickets?
Below is an example of some airlines that sell transferable airline tickets and their transfer/name change policy. Please note that flight tickets can't be transferred if you've already checked in or flown on one leg of the journey.
easyJet
easyJet allows you to transfer the person on a flight reservation to another person by paying a name change fee. Fees are less expensive if you transfer the ticket at least 60 days before your flight. Past 60 days, the fee will be higher and — if you request to change too close to the flight — the airline has the right to refuse.
Ryanair
Ryanair allows you to transfer your flight to another person but it will cost a fee. Depending on your flight, it can sometimes be cheaper to buy an entirely new flight ticket. Name change fees start at £115 GBP per passenger and can be made up to two hours before the scheduled flight departure time. If you booked a flight with Ryanair, you'll have a 48-hour grace period where you'll be able to make minor changes to your name.
Vueling
Vueling allows you to change the name and transfer your booking to another person for free if it's requested within 24 hours. After 24 hours, it'll cost €50 EUR per person/per way + the fare difference. Name changes can be made up to two hours before the scheduled flight departure time. Please bear in mind that name changes cannot be made if you've already taken one of the flights within the booking.
WestJet
Changes and transfers within 24 hours of booking are free. After 24 hours, WestJet will allow you to transfer the person on your companion ticket but it will cost a fee. This can be done up until two hours before your flight is scheduled to depart.
Wizz Air
Wizz Air allows you to transfer the passenger on a flight to another person up until three hours before the flight is scheduled to depart. This will cost a fee, starting at €45 EUR per person/per way.
Transavia
Transavia allows flight tickets to be transferred to someone else for a fee. The fee is undisclosed and will differ depending on the circumstances. Name changes are allowed until 2 hours prior to the flight departure time.
Flybe
Flybe allows passengers to change the name on their ticket and transfer the flight to someone else if they pay the name change fee. If passengers have purchased the Get More or All In fare, they'll be able to transfer their ticket within 24 hours for free. If they've purchased the basic Just Fly fare, they'll have to pay a fee to transfer the ticket, even if it's within 24 hours.