I've flown with my son multiple times. Here are some things I've learned...
Take your own portable trash bag - they seem to have so much trash as a little one. I used a little diaper trash sack - the scented ones - just because they are so small and mine had handles.
I took a little backpack of his (since yours is younger, just use your diaper bag) and put new toys that he'd never seen before.
I was all about the DVD player. When my son was little, he was mesmerized with baby einstein. It was a huge distraction. If you have an ipod that you can upload pictures onto, upload pictures of him and pop that out when you need it. My son has always LOVED pictures of him. That or movies of himself.
I nursed him going up and coming down. That also helped him fall asleep.
The BIGGEST life saver ever for me was I purchased his own seat. Even when he was under 2. I called the airline and asked for the cheapest fair possible. Told them it was for an infant. This way they can sit in their carseat where they are comfortable - and if they fall asleep, it gives you time to relax. You probably already have your tickets, but it may help in the future.
I think one thing that may help you with your layover is a baby bjorn or sling. My son often fell asleep in his. The rocking motion while walking always knocked him out. I never gave him benadryl because for some kids it wires them rather than making them sleepy.
If I think of anything else I'll add more. Let me know if you have any questions. Oh, and if you are taking your stroller and check it at the gate, don't put a bag on it. 2 times they sent it all the way to baggage claim. They didn't realize it was a stroller. :-)
Good luck!
S.