Originally Posted by
brunos
Many airlines have introduced fare brands, like AF light, standard and flex on AF.
Those 3 brands can book into different fare buckets, like Y, B, M, etc for Flex. Even those can have different fare basis like K********.
AF brands are mostly decoupled from fare buckets now. There are light, standard, and flex fares in most of the fare buckets, so for the most part the bucket availability is the same for light and flex. However, the light fares tend to only be filed with stricter conditions (e.g. longer advance purchase or stay requirements or perhaps even (a la what the US airlines have started bringing back, requiring accompanied travel)), so there are occasions where there's bucket availability for light fares but your trip doesn't satisfy other requirements for any other light fare.