Even though your flight is a short one, it can still be challenging for the kids to stay at a limited space. The car trip to the airport, waiting in lines, waiting at gates, flying and so on – together it can add up to quite some hours.
I make sure my kids go to a park or a playground the day before the flight. A lot of running, a lot of climbing – that keeps their spirits up the next day. And it makes my flight easier as well. But it means I have to pack one day earlier. Which turns out to be quite good – even grown ups feel good playing in the park the day before the flight =).