In future, it would be possible that airline company’s could he paying for passengers to book a flight with them. It comes as WOW - a budget airline - have cut prices of international fairs and want to get better at selling additional services.
So, for example, the flight itself is free/they will give you money, and they would hope in return for you to buy things like speedy boarding, or choose your seat, or seat upgrades, in flight meals and all the rest. Another way they make money is through selling hotel rooms when you book a flight, and other things like hire cars.
This does appear to be the general trend of the industry.
These free flights/paid to fly flights, it also builds a relationship with the customer.