Right on Hamilton airport property (across the parking lot) you will find the "Canadian Warplane Heritage Museum". I would have no problem killing 3 hours here. You didn't mention the time frame you will be there, but the museum is open year round 7 days a week from 9am to 5pm.
I would post you a link to their web site but I am new on these boards and don't have enough posts yet to provide you with the link, but I urge you to check out their web site, it has a virtual tour and lots of information.
This museum I hold in high regard as it is home to one of only two "Avro Lancaster Bombers" still flying, the only one in North America as the other is located in England. If the weather is nice when you are there you may be lucky enough to see it out flying, its really something to see, never fails to stir emotion in me and make me think what our Veterans went through.
Other than that, there isn't much else to do at the Airport as it is located in a sort of rural/farming area and the Museum is the only thing within walking distance. If you and your family enjoy history, I think this would be perfect. Anyway sorry this is so long (can you tell I like this place) Enjoy your trip and don't forget to check out the website.
Cheers.
Don.
