When I flew for the first time with my daughter, I had so many questions. What to bring, lap or seat, and most importantly, how to change a diaper (or nappy) on the airplane.
Our first flight was a long-haul from Australia to the U.S. There would be many diapers (nappies) to change.
It might seem silly, but I wondered and so might you. Most airplane bathrooms will have a change table. It usually flips down from somewhere over the toilet. Ask a flight attendant if you can't find it.
See photos for steps:
See my post about packing a carry-on for suggestions on ziplock kits, particularly handy for airplane diaper/clothes changes.