I fly with my son annually and we took our first trip when he was about 8 months old. He is now 5, and having been on at least 7 plane trips with him, he is now a well-mannered experienced traveler who loves planes and does really well in airports.
The liquid restrictions onboard planes does vary for traveling parents with infants. I would still recommend putting certain toiletries like shampoo in your checked bag but a parent is allowed baby bottles and children's medication at slightly larger volumes. Check the Transportation Safety Administration website to be sure but some of those restrictions have been laxed.
I will also say that I flew last month and had forgotten to pack away a couple of liquid items, but no one pulled out my hand carry to perform a hand search.
My hand carry is packed with all his favorites - toys, blanket, stuffed animal, books and games. Snacks of course, and beverages, plus a bottle of Children's Tylenol and Motrin just in case. An extra change of clothes, and all the other necessities.
A beverage at takeoff and at landing will help with the ear-popping.
I think the trick is to keep them happy, pace yourself properly and be flexible. My son always immediately picks up on my stress, which makes him worried and irritable. But when I'm happy and easy going, he is usually more comfortable. Plus I keep close tabs on whether he's happy, or hot, or hunger or if he needs something right away to keep him content.
If you didn't buy your ticket already, try to time your flight when it would be nap time. That always works like a charm. And if you have a layover, try to find a schedule with enough of a gap, so that if you do have to cross terminals, you'll have time to do so, while also accomplishing diaper changes and feeding time, and anything else like that.
Airports can be a great adventure - lots of fun sights, different noises, different people.
Just take everything in stride. I have found that most people, especially airport employees, are very helpful to parents and so they are usually very accommodating and understanding. And since I work hard to keep my child content, then he doesn't end up being that screaming, annoying kid that everyone on the flight hates. I can't tell you how many times, I'll have passengers say to me, as they're departing, that my son was so good and that they didn't realize or they forget that there was a young child on board.
I can't think of anything else at the moment, but if you have specific questions, please feel free to message me. Like I said, I've taken my 5-year-old on more than 7 plane trips (including 2 cross country trips) and have rarely had a problem.
Good luck and bon voyage!