I'm looking at booking flights SLC-ZRH and return. Google flights shows cheaper options when booked through KLM website, rather than on Delta (even though 3 of 4 flights would most likely be on Delta Metal). I can't figure out how much KLM would charge on top of the economy fare to select "regular" seats, esp. on the TATL legs. If booked through KLM, could I still go to my Skymiles account and select seats for the DL metal flights? Sorry if this is covered somewhere else, I could only find very old threats on this subject. If booked through KLM, could I still get Skymiles? Is it fair to assume that KLM fare + seat assignment = Delta fare? Any other downsides to booking with KLM, like less options if delayed/cancelled/rerouted? TIA