VAP--- totally agree some are confusing paying for seat selection ($25-$35 in most cases) with paying to upgrade to the next class of service ( EconomybPlus) or to a preferred seat like exit row. These are totally different things.
The OP started this thread to ask about Air France wanting her to pay $25 or the privilege of choosing her own seat in Economy in advance, rather than accepting what the airline assigns at check-in. More and more foreign carriers are doing this, but it comes as a surprise to some who have not flown abroad recently.
I thought it might help to prevent surprises if we could make a list of such carriers, from personal experience. One person seems to think that is pointless, because there are so many exceptions (status, etc.) but I expect people who qualify for the exceptions know all about this.
The higher prices mentioned here-$100 or more---are not for the privilege of choosing your seat in Economy (regular seat) in advance. Those higher prices are class upgrades---a totally different thing. Only on Delta it is a kind of hybrid situation---one can book into Economy and then pay $100 or more to select a seat in Economy Comfort. Whether one can book directly into one of those seats on Delta I do not know. We have never flown that airline and probably never will as our miles are with BA. And on other airlines, advance seat selection and class upgrades are totally different---and priced accordingly.
Bottom line: many people think $25 is a small price to pay for a favored seat (aisle or window) on a 9-10 hour flight. But if you don't mind risking a middle seat, you can skip paying and wait until check-in to see what the airline assigns you. And some airlines ( like BA),will let you choose a different seat at that time if one you like better is available.
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