One thing I forgot: although you can earn Flying Blue miles on Etihad flights, you won't earn XPs so the flights won't count for status progression.

(The only exception: If an Etihad flight is booked from AF or KL and flown under an AF or KL codeshare flight code - as part of a "larger" AF/KL journey that involves travel on either AF and/or KL as well as on Etihad - then such an Etihad flight would earn both Flying Blue miles and XPs, because it was booked as an AF/KL codeshare).