Traveling by air with children: a quick checklist for the concerned parent

• The day before you leave, give everyone a backpack and tell them to pack the toys they want to bring. After they've gone to bed, remove 65% of whatever they stuffed in there. Add a couple of very small new things to generate goodwill and distract from what's missing.
• Everyone with a luggage allowance gets a rolly suitcase. This eliminates a lot of fighting over who gets to pull it; however, make sure you can fit the child one on top of an adult one for when they inevitably tire and have a hard time just carrying themselves.
• If traveling with a stroller, remember that you'll have to empty and fold it to go through security, and again to get on the plane. Do not stuff every last thing in there as if it were the trunk of your car. It is, however, invaluable for holding coats and backpacks once you've checked in. Sometimes you may even opt to let a small child sit in it - but then you'll have to carry the coats.
• Abandon hope of getting people to eat healthy snacks in the airport. Airports are for McDonalds opportunities. Burger King if you're pushing the boat out. If you must bring healthy snacks, save them for the plane when children are trapped and the options are fewer.
• A new coloring book or sticker book for the plane is a nice idea, and might even keep a child occupied. If you give a child under five a sticker book, be prepared to spend much of your journey pushing up the stickers from behind the page so that they can lift them off. Don't forget a nice new pack of crayons or markers for the coloring book. The ones you already have at home will definitely not suffice. A brand-new pack of eight for each child will do nicely.
• Being read aloud to is an option that many children are happy with. Choose a book you're comfortable reading in front of adults as well as children, because all your fellow passengers will be listening. (Alternatively, I believe audiobooks are a thing you can get. I'd look into it, but I think my husband secretly likes the attention.)
• Bring a large backpack for your own carry-on. On the outward journey it should contain 1) Secret new presents, only to be produced at the gate or on the plane, 2) Clean under/outerwear for children and/or adults in a large ziplock bag. 3) Diapers and wipes as needed. More than you think could possibly be needed, just in case. 4) More wipes, in the most easily reached pocket, in case you can't find the other ones. 5) Adult emergency chocolate/granola bar. 6) Book, Kindle, or magazine, if you're an optimist and think you might get a chance to read something.
• On the way back, most of this space will be filled with Christmas presents, birthday presents, large stuffed animals, baby dolls, new boots, or duty free alcohol. The children will manage just fine without extra new airplane presents at this point. Try to remember the baby wipes, though.
• If all else fails, feign ignorance. Those children? No, they're not mine. Perfect your gaze into the middle distance and don't forget the earplugs.