1. Don't Forget the Snacks. Bring food, no matter what. If you let the kids' tummies get empty, their blood sugar will start to drop and things will get irritating quickly. Not only will eating give them something to do (and make it so they can't talk for a little bit), but it will keep them feeling happy and satisfied. You probably want to avoid insubstantial and sugary snacks that are just going to give your kids an energy rush. Try to focus on things like string cheese, beef jerky, nuts, crackers, and other foods that are relatively good for you.
2. Manage Their Expectations. Keep your kids in the loop, so they know what's going on and aren't going to be anxious about not knowing when things are going to get moving. Tell your little ones about any delays that might be happening, and let them know to the best of your ability when you're going to be moving along. This way, you can spin the situation, telling them that you only have so much time to figure out how many fun things you can do before your flight leaves.
3. Do Some Exploring. Believe it or not, the airport is a pretty cool place when you're a little kid. Sure, they're the worst places in the world when you're an adult (most of the time), but they're definitely full of a lot of things that little ones like to look at and play with. Definitely make sure that you supervise your children closely, but if
you've got a few hours to kill, take them around the airport and ride some escalators. You can do some plane spotting while looking out a big window and talk about all the different types of machinery that you see on the runway.
4. Get Some Exercise! Find yourself a vacated gate and see if you and your kids can get a little workout in while you wait for your plane to be ready. Do some calisthenics with your little ones if you can find a spot where there's nobody around. Not only will this give everyone some exercise, but it might just tire your kids out enough to put them to sleep once they get on the plane.
5. Bring the Reading and Coloring Materials. These days, a lot of parents simply grab the smartphone or tablet when they're looking to entertain the kids at the airport. You can definitely do plenty of fun things with these devices, like reading witty quotes on http://www.quoto.com or watching a hilarious video on YouTube. Your little ones can also be entertained without the use of a screen, however. The airport is a great place for you to break out the coloring books and crayons. Regular books are great, too. This will give your little ones a way to keep themselves intellectually engaged while you're waiting to start the next step of your trip.