Flying with Kids: Tips and Tricks

Travel Advice with Kids
In a few weeks I’m taking my 6 year old from Perth to NZ. I wanted some travel tips, last time I took him he was 1!
The flight over is 6 hours and a day flight. The flight back is 7 hours and a night flight and we will be in the airport for 4 hours before the flight which takes off at 7pm (he usually goes to bed at about 7.30pm). What would you take/do in the time?
At the moment I have a colouring book, textas, a toy plane. Any ideas? Tips?
Thank you