C.B.
I'm in sales and I travel all the time. I am also a single mom so I take my son & my granny nanny (my mom) with. My son had taken 18 flights by his second birthday. Here is what I can advise:)
Take your car seat with you to the gate. If there is an empty seat on the plane they will move passengers so you can put your daughter in her seat. This is a life saver if you can do it. Kids are used to riding in their seat and my son usually did really well. If there is not an empty seat they will simply check it at the gate.
I had a theory to fly when my son would be tired so he would sleep on the plane. He was so social that did not always work well. The thought of him up and missing a nap, was not a happy thought for me flying. He did ok the times I tried it, but rarely went to sleep. If she goes to sleep easily in public you may want to fly during nap time. My son did not. I did try fly during an "eating" time. I would bring his favorite things to eat and that would take up a whole bunch of plane time. I also brought a mini dvd player (if she likes movies), some quiet toys, and books.
I usually gave him some sort of decongestant with the theory that might help his ears. You might want to check with your doctor on that one. I also made sure I had something good/special to drink during take off & landing. That way the sucking action really helped his little ears pop. I nursed until he was 12 months old so he would just sit under the blanket sucking away happy as a clam. He never really seemed to have problems with his ears.
Good luck. Have fun and don't stress about it too much. Anyone that has kids knows sometimes they cry. Anyone flying that doesn't want to be disturbed should bring a head set:)