I fly cross-country a lot with my daughter (just the 2 of us) she is nearly 2 so have a few suggestions I've done and some that I have been saving for the right time as she gets older. In all the trips we've done, she's never cried or been unhappy except the one time she had colic at 6 weeks of age.
Anything that I bring on the plane for her is either new or it's just something that is for travel use only so it's always new to her. I pack the supplies in my suitcase for the return trip, I rewrap everything as well as anything new I pick up during the trip. Anything I bring as a distraction is in a large ziplock bag-- keeps the items organized and easy to get out. typically I have 10 ziplocks organized into 2 or more 2.5 gallon bags.
DVD player: make sure the headphones have noice cancelling part to them, some planes are noisier than others. Have the child wear them at home to get used to them -- make adjustments at home so you aren't scrambling on the plane. Make sure the battery is charged.
Instead of wrapping the little gifts, try putting them in plastic Easter eggs; I do small toys or place a few M&M's in them. Wrap them with Saran Wrap (different colored wrap), use a lot so it takes some time to undo it all put tape all over it as well; you have a 5-10 minute project and then the prize. Normally she wouldn't get the small toys (choking hazard) but she is going to be seated and I am right there watching so I don't worry about it. Once she's done playing with it, into the backpack it goes until next time.
Buy a wallet, put in old ID's, expired gift cards, pictures, fake money, etc. A big hit with the smaller ones because we all know how interesting Mom's wallet is....
Cheerios and dixie cups offer many minutes of sorting fun.
cash to buy those seated around you a drink if your child is acting up-- buys good will. Actually acknowledging that it could happen when everyone is seated helps; it lets them know you are aware it could happen and decreases the tension.
A small box of chocolate for the in-flight staff-- they love it and will go out of their way to help de-plane and with extra snacks and taking away all the saran wrap and other trash. They know a happy child makes the whole plane happy and if you are trying to make that happen, they will be right there with you.
My daughter loves books so I always bring several new board books as well as a couple of favorites.
Scotch tape, several rolls. I lay strips of it on the tray and she spends over a half hour peeling it off and rolling it up. I went to the Dollar store and bought a several rolls-- I passed it around to other parents who needed a distractions with their child.
Small cans of playdough with the cutting shapes--
Travel Doodle-pro
A spare (or 2) loveys-- stuffed toy she can't live without (that I tie to the backpack).
One we will be trying a large shape puzzle--16 pieces at most. Another suggestion is cutting out pictures of
disneyland and bringing glue and a large sheet of paper-- make a collage of what will happen at the parks.
She's not into coloring or painting yet but eventually I will bring the books that were suggesting in an earlier post.
I pack everything for the plane for her in a hiking backpack-- it's big but it fits under the seat infront of her and doesn't impact my legs. It's easily reachable and has tons of pockets, places to hook things, slots, etc. It is heavy but doable.