Activity Ideas for Plane Ride with 3.5 and 2 Yr Old. . .

You sound well equiped. I bring snacks as well. With all of those options that you have, I wouldn't worry- they should be fine. The take off, landing, magazines- take up a lot of time as well. Have fun.

If you have iPhones or iPod touches, load them up with kids games. I like 123 color, glow doodle, lunch box, peekaboo barn, angry birds. Those are just a few toddler friendly ones. Also my 2 year old loves to look at pictures and videos of himself and his brother on my phone.

You can also buy cartoons in the iTunes store. We put every episode of Thomas on one for a long road trip, worked like magic.

Lots of snacks and stickers

Kids always do better on the plane than we thought they would. Have a great flight!

This is a small thing, but I found it saved me a headache or two - at Target, you can by triangular crayons - they don't roll all over the place, so don't get lost, and you don't have to crawl under seats to get them.
We take my husband's laptop and the kids watch The Wiggles, etc., on them, and that's a big help.
I'm surprised about play-dough - just seems too messy for a plane.
We also bought a container of fruit (strawberries, etc.) once we got past security and the kids munched on that while the plane took off. It worked well!
Spare clothes are a good idea in case of spillages.
Have a great trip!

Earplanes for their ears (if they will let you put them in). Also, my kids would swallow gum which I use to keep my ears from popping...so I bought a HUGE bag of gummies...the larger sized the better since they take longer to chew. They could chomp away on them releasing some of the pressure in their sinuses and ears.

I had another bag of them for a flight with just my hubby and I to snack on since they were leftover from gummy kabobs we made for Valentine's Day. Three kids were flying with mom and dad, and the two youngest (both under 3 years old) were crying and screeching for about 45 minutes straight. I finally got up the courage (you never know how parents are going to react to starngers offering food items to their kids) to flag down a flight attendant and offer them to their kids. I explained about the pressure and how it worked for my kids...the kids were so excited by the unexpected treat that they were quiet for the rest of the trip (3 hours). The flight attendants all came up and thanked me at the end of the flight along with 3 passengers.

I'm gonna say yes to the playdough. It was helpful to make one long "snake" to put on the edge of the tray table, so that the markers didn't roll off(same would apply to the matchbox cars). Of course, I wiped down anything I could with sanitizing wipes first....ick.
If your older two are good with sitting and being entertained by the DVD's then,yes, the computer is good. However, if they aren't interested, much, in movies, the plane ride won't make them want to watch. Will you have headphones? In order not to bother the other passengers, unless there are headphones, you won't be able to turn it up loud enough for them to hear.
I would also make sure you have empty cups with straws or sippy cups. The flight attendants will give you a small, very full cup of juice, or whatever you ask for. This cup, most likely, will get spilled. On YOUR lap. LOL!!! Ya know those plastic cups you get from restaurants, with the lid and a hole for the straw? Perfect.
I would suggest taking those plastic chains for the 6 month old. Attach his/her toys to them if possible. It's a lesson in contortionism trying to fetch thrown toys and binkies off the airplane floor. It will also keep them cleaner, if they don't actually make it to the floor.
All the other suggestions are great, for a carryon! I would pack a couple toys that are new and maybe one comfort item, but I wouldn't go overboard with too many toys and such. Carryon bags need to be able to be stuffed under the seat in front of you, so they can't be too big and bulky. You will be getting into them quite a bit, so putting them in the overhead compartments really won't work too well.
Make sure you have a change of clothes for each family member!! Not just the kids, but you and whoever else will be tending to the kids. Spills happen,not to mention if your bags don't follow you to your destination.
Usually, I would be wrapping one of the new toy items in paper, so that it can be unwrapped, which adds to the excitement.But, seeing as how it's so close to Christmas, I don't know if the unwrapping part will be as exciting.
While waiting for the flight, let your kids run and play as much as possible. Get any pent up energy out, before getting on the plane:) It can be nerve-wracking, taking kids on flights. However, the calmer you are, the less the kids will feed off of your anxiety. Easier said than done, I'm sure. In my experience, most passengers have been patient and helpful. I hope that's the case with you, too.
For the take-off and landing, make sure you have drinks ready. A passifier won't make your 6 month old swallow so much, so a bottle, breast, etc. is best. For my kids, I always brought gum, but yours are a little young for that. Last time, I had a twizzler licorice stick for my 9 month old. I don't normally give her twizzlers, but she wasn't interested in the bottle at the times I wanted her to be. The licorice was a hit and she didn't suffer any effects from the pressure changes.
Good luck to you and have fun!!

About 2 weeks before we went to Disney World in Jan. 2010, I packed each of our kids (About the SAME ages at the time as yours!) a "carry-on" backpack bag. In it I packed:

*2 new toys/items from dollar store'
*water (sippy) cup (filled it the day we left, went through security fine)
*juice box (went through security fine)
*4 or 5 smaller toys from our toy room (wanted to pack early so they would seem "new") -cars, barbies, small magna doodle, etc.
*small pillow and blanket
*small stuffed animal (they each have some favorites)
*4 SMALL books each
*a couple snacks (crackers and such) in small Tupperware dishes to keep from smashing
*notebook, pen, pencil, pack of markers
*beach ball (easy to inflate/deflate and FUN to play with while waiting at airport!)
*balloons (fun to play with, cheap to through away)

We choose NOT to borrow a dvd player from my mom. GLAD we didn't! It would have been a hassle to keep with us and make sure not to loose or get stolen! I also don't know if play doh is a very good idea......? The flight attendants may not appreciate that.

We had NO problems staying busy on the plane! The kids loved it. Were not bored at all. And they gave us snacks and beverages on our plane so that took up a good 1/2 hour of our 4 hour flight.

Not sure if the play doe on the plane is the best idea or not. Stickers, coloring books, little toys, books, dvd are a great idea. Don't forget snacks and any lovey they might have (or pacifiers).

Good luck.

One thing we brought with us when we flew was Crayola Modeling Magic, instead of play-do. It sticks together much better than play-do and doesn't leave all those messy bits that get worked into the carpet, etc. It was MUCH neater and was easy to work with. If your child makes a creation that they don't want to destroy, you can leave the modeling magic out and it will harden and they can then draw on it with marker if they want or whatever. It comes in little plastic bags in all sorts of colors. I brought some ziploc bags to put the opened bags in since the bags they come in aren't reclosable.

I also keep my eyes out and check dollar bins in stores frequently for fun things I think the kids would enjoy. I tuck them away and don't show them to my kids so that they're "new" when I bring them out in the plane or car. I've used those little mazes with the metal balls that you have to maneuver around, books of puzzles, reading books, paper and crayons, sticker books, random toys and we also have three hand held electronic games - just cheap ones I've picked up in clearance bins or whatever. My kids don't know how to play Solitaire, so I usually get that one, but they love the Yahtzee and Deal or No Deal ones. Your kids are a little young, but mine also really like Mad Libs, and they were fun even when I had to keep defining "verb" or "adjective" for them. They loved coming up with words and then hearing the story in the end. I also let them pack a few items of their own that they think they'd like to play with, as well as a favorite stuffed animal, so they had some say in it. Good luck! I agree with other posters that they will probably do better than you think. Stay calm and have fun! You will most likely never see your fellow passengers again, and many of them have probably walked in your shoes before and will understand.

You have good ideas. Also pack some snacks. I always make sure to bring some new activities along. I pack a backpack for each of my kids with surprises that they can't see until we are traveling. A new DVD, new sticker books/activity books. They are always excited to see what I've brought for them.

Travel magna doodle. Got one for my 2yo for our last international flight and it kept her busy for about 20 mintues at a time.

A couple of containers of playdough and cookie cutters works well for me. Also, I can't emphasize little snacks enough. Things like goldfish, crasins, things you can give them just a couple and then a couple more. -Takes up time. Also, as a special treat I give my kids a lollipop each on the way up and the way down. It helps with their ears and keeps their mouths occupied for a while. You can also play "I Spy" with your 3.5 year old.