Air France KLM’s Flying Blue program has become the latest one to jump on the waggon to offer monthly mileage subscription plans, allowing you to purchase miles at a preferred rate.

Purchasing miles at the most common rate of 2 to 2.5 US/EUR cents per mile is, in general, not a good idea and really makes only sense if you are short of a few miles to claim that long-haul award flight in Business or First Class. Regular promotions to purchase miles may take that price down to around 1.5 cents, but don’t really change the reasoning.

If you are willing to commit to a monthly purchase plan, the price can be reduced further, in the case of Flying Blue to as low as 1.1 EUR cents per mile. This is still not a deal you should sign up with eyes closed, but if you do the maths (and also include the fees and taxes to be paid on award tickets), there can actually be some cases where such offer starts to make sense.