My 13 months is completing her second transpac trip in a couple of days: SGN-NRT-IAH-IAD-LAX-SFO-SGN. The first trip was around 4 months mark.
We are very lucky that she's been a great travel companion. In fact, we flew F from IAD to LAX last week and the couples behind and beside us was surprised and gave her 91/100!
Prepare and pack efficiently on the plane as well as keeping her favorite toys + Baby Einstein videos handy.