Dear Rimpeltje,

01. S after the flight Number just determined your booking classes in Economy. (There are several Economy Booking Classes in which each fare determined your fare rule, the highest fare you pay the flexible rule you get vv. Typical Booking Classes that exist in economy are Y,B,M,H,K,L,E,S,R,N,T,U,V,W,Q,G and for Business mostly C,D,J,Z and First are F,A,P)

02. HK1 means your status is confirmed and no one can take your seat unless you cancel it or no show at the airport. HL1 means your status is waiting. Sometimes they use KK for confirmed status and KL for waitlist.

03. Y just determined that you seat in Economy Cabin (for short we refer to Y Cabin and S just your determined your booking class ticket in economy)

I hope these answers help you a lot.