Any time longer than about a minute sitting around doing nothing, either on the ground or in the air, calls for distraction techniques to be employed. I usually bore them stupid with long convoluted explanations of the intricacies of aviation procedures and technology. Kids seem just as interested in all the goings on on the ground as grown-up kids like me enjoy watching the planes. There are always lots of tugs and baggage trolleys moving around (except if you're going to LHR T5, I suppose), as well as bowsers, buses, and men in fluorescent suits with ping-pong bats. Once airborne, a good knowledge of meteorology can come in handy (eg why clouds bubble up, look like cotton wool, etc.), together with a vivid imagination (looks just like Santa's beard). My kids usually enjoy a sick bag colouring-in competition, with the artwork taken with us on leaving to show whichever relatives we're off to visit. They're usually quite serious about drawing some good pictures. My 4-year old daughter loves anything pink or purple, so when she saw a picture of a WizzAir A320, she was determined to go on one. I was, of course, only too happy to oblige, and we had a nice trip to Poland - WizzAir even has pink airstairs in Warsaw, so she couldn't get on fast enough! Hope your trip goes well.