I flew out to New Zealand last year and there were plenty of families taking babies less than 1 from Birmingham to Auckland. The fuss was minimal compared to the poor families taking children of ages 4-12. They were awful to deal with, they're old enough to understand that they have several very long flights ahead of them but not old enough to sit down quietly. They became very grouchy very quickly, then on the last flight out to Auckland they were screaming, climbing seats, tantruming etc.
I was lucky in that I could put my NC headphones on for most of the journey.