I purchased a ticket from PIT to CWL with stops in DTW & AMS through a 3rd party website. I'm 99% certain it's KLM, but the ticket lists Endeavor Air, Delta. & KLM Cityhopper for the connections.
The return is similar, I'm thinking they are Air France flights, with the connection flights being KLM Cityhopper, Air France & Delta.
I've been able to view my booking on Air France, Delta, & KLM. I just want to make sure I check in at the right counter.
Also, since CWL is my final destination, that's where I'll go through the questioning with the immigrations officer, correct?