Up to now I was sure that you could get an award on any AF/KL flight as long as a seat is available for purchase (however pricing could be skyrocketing for the last available seats)
Now I have seen that some flights are no longer offered for awards although seats are still available/sold. That goes through all cabins.
Here is an example for NUE-LAX on March 1
1. The KLM flight NUE-AMS-LAX departing at 6:00am is not offered anymore
2. The 6:10 AF flight from NUE is only offered as premium economy award, no eco and no business class award available although all cabins are on sale.
Award search:
Revenue ticket flight search
I hope this is an error - or is it the new reward availabiliy?