There was a time when checked bags, seat selection and your meals all came as standard on commercial flights. But that all changed with the rise of the budget airlines, says Jay Sorensen of US aviation consultancy IdeaWorks.
It was in 2006 when UK low-cost carrier FlyBe became what is believed to be the world's first airline to start charging passengers to check in bags. It charged £2 for a pre-booked item of luggage, and £4 if the customer hadn't paid in advance.
Other budget carriers then quickly followed suit, with the so-called flag carriers or established airlines then also doing so, at least on shorter flights.
In 2008 American Airlines became the first US airline to charge a fee, $15, for the first checked bag on its domestic routes.
Mr Sorenson says such traditional airlines felt they had no choice when they "began to realise that the low-cost carriers were providing very significant competition". He adds: "They felt they had to do something to meet that."