Impromptu joining of a skytem programme
Hello,
I had some unforeseen business travel lately, 2 intra-us / transatlantic in first on CO/DL.
I'm not currently part of any skyteam program, traveling on StarAlliance mostly.
I'm now wondering, which program to join, to credit those flights to: CO, DL, AF, KL.
Being based in Belgium, I tend to Air France, but I hear negative comments about their Fréquence Plus program.
Basic usage of miles is for upgrading discounted tickets.
Any hints would be highly appreciated.
Thanks