This is a tricky age because he's too young for a lot of toys. I assume he's walking so plan to spend a lot of time in the aisles. Coloring stuff is good to bring.
You will have an easier time if he has his own seat and if you bring his carseat. They are calmer and easier when strapped in. Plus, while he's sleeping, you can get to the lav (tell someone nearby where you're headed in case he wakes up). Turbulence can hit and he'll be safe!
Ear problems are entirely overrated as being a problem. Also, while sucking helps, it's not on take-off and landing. It's actually the whole way up, ascent, and at the TOP of decent that passengers of all ages have problems. Make sure he's awake as the plane starts to land. Just being awake will probably do it.
Go to the ped a few days before leaving and have him or her look in your child's ears. Healthy ears with no infections should be able to handle the pressure. Bring Tylenol if that makes you feel better. The problem with the ear gizmos is that a lot of small children wont actually cooperate with having those things stuck in their ears and it might create more problems than solve them.
I do suggest changing him standing up. Don't laugh! This is seriously much, much easier for travel in general. No need to look for a changing table. Toddlers HATE lying down in strange places. I go into more details in this totally non-commercial article I wrote for the local American club years ago;
http://flyingwithchildren DOT blogspot DOT com (just put real dots in, Yahoo wont let me post the link-sometimes they do, sometimes they don't...)
I'm neither for nor against drugging kids inflight but only consider it if your flight is more than 5 hours, talk to your ped and try it at home first. Twice I saw kids wired on that stuff! Not a pretty picture...
Also details about the carseats and how to get them through the airport. My daugher's carseat is 25lbs and I'm alone with three kids and I can manage it! You can too.
ex-F/A, 13 years, 2 carriers
three bilingual, dual national children, I fly alone with them about every six months between Europe and California, plus shorter flights...