I was on a short flight wearing a kn95 mask. during landing, the man one seat away from me became sick i believe into the air sickness bag. is it likely i caught something contagious from him? or more likely motion sickness?

You were wearing an N95 mask which would be very protective to start with. Also, planes have such good airfiltering systems that contamination from another passenger on the flight is so much less than sitting beside someone in the airport. When someone vomits, the little particles spray and so contamination of your hand and clothes can happen. Good washing of your hand before you eat was needed.