My DD (now 8) and I have travelled all over together by plane and here are some of my lifesaving tips:
1. Do not bring things that easily fall to the floor, eg: crayons. With the way you are squashed in these days, you will not be able to bend over easily to retrieve. When my daughter was the age of yours, we used the travel Magnadoodle since the "pen" is attached. We also brought Beanie Babies, bc they are littler than regular stuffed toys.
2. Bring healthy snacks and juice boxes. There is nothing worse than those cheesy little plastic cups on the plane in the hands of a little one. If you are on a meal flight, call ahead & ask what the kids meal is. We've gotten pbj, chicken nuggets, and other kid friendly stuff. And do not count on milk. Often they do not have it.
3. I am assuming you have purchased a seat for the baby. Make sure your child rides in the car seat, and don't make exceptions, just like in the car. Also, bc the tray will likely not come down, try to find one of those lap desks. Better yet, they do make one that can attach to the car seat. I think I saw it One Step Ahead catalog. Also, I hated the bulhead seats, and they often offer those to you when you are traveling with a baby. I liked having the space under the seat in front of me to stow gear.
4. Do not check your stroller. You can take it right down the ramp to the plane door, fold it up and then leave it. They then put it in the cargo hold for you, and deliver it as soon as plane lands right back next to the door. (If you are connecting, you will get it at the connection point, then you'll repeat the process.) It's awesome! Also, I am not sure how many helping hands you will have, but I always used a backpack to keep my hands free. Also, re: the car seat: I bought one of those fold-up luggage carts that I would attach the car seat to. Those suckers get heavy after awhile!
5. Since Sept. 11, they are strict about carry-ons. They count your purse! I travel weekly for business, and used to carry a purse, briefcase & wheelie. I got really sick of having to check my wheelie, so now I pack my purse and just throw my wallet into my briefcare or backpack.
I hope you'll find these tips helpful!
ps: Trish -- we summer in Casco, ME - practically neghbors!