My first trip was not too interesting: 1980 interviewing at schools. BOS-ORD-SAN (UA--channel 9 even then), LAX-SFO (UA), SFO-BOS (TWA). UA flights on 737's, TWA on a L-1011 (I think).
My daughter's first trip was more memorable. 1991, 1 day old, SAN-SEA (AS) on a MD-80. As new, and a bit surprised parents we were thankful she slept almost the entire way. She still enjoys flying, though now she wants to be awake and in front!