I have flown 3 times with dd, once around 14 months, then 18 months, and 20 months.
If you have a long trip (we flew from TX to OH when she was 14 months) it really helped us to break it up with about a 1 hour layover. We were on the plane about 1 1/2 hours, then I let her blow off steam and run around the airport during the layover, then another 2 hours on the plane. That worked *really* well for us. She wouldn't really sleep on the plane because it was really noisy the darn pilot kept on coming on the loudspeaker with inane chatter
Nursing on take off and landing is good or a cup or whatever. Riley had NO problems with her ears.
We brought her carseat and gate checked it. One flight wasn't full (we didn't buy a seat for her) and we strapped the seat into the empty seat by us and let her ride in it. That was the only time she napped.
I bought a travel magnadoodle which was a BIG hit, stickers, and just a pen and paper. On the first trip I brought a MILLION toys, which were totally unneccessary. I did bring a little bowl of blueberries, which are just her all time favorite food. Also raisins in a little box (letting her pick them out of the box killed time
) Hiding little toys and whatnot in the barf bags for her to figure out. Flirting with the little boy in front of us. I'd bring a couple of new toys, but not too much....