We are traveling to NZ with our DS, who is nearly 4. We're flying from Heathrow and have a few hours layover in Singapore, same on the way back. It's a 29 hour journey 
How do people move around airports with a child this age? We depart Heathrow in the evening so I know he'll be tired. We've been tossing up whether to take a light folding buggy, even though he doesn't normally use one anymore. Otherwise I think one of us is going to end up carrying him, which we won't enjoy as he's tall for his age and really heavy! On the other hand it seems silly to take the buggy just to use in the airports.
Does anyone have any recommendations for child headphones to use on the plane? I have a small head and the standard airplane ones never fit me, so I'm sure they won't fit him.