Originally Posted by gpan
2) FB is more yield based, and mileage only exists if the customer is paying a higher yield ticket - other fare classes earn nearly no mileage
Something of an exaggeration (FB is no BAEC!). Except for domestic French flights, only the very lowest classes on AF and KL earn only 25% miles in FB. Most coach classes are 100% earning, with a few, used mainly for consolidated/group fares, earning at 50%.