I traveled with my daughter when she was 4 months this summer and it went great. I'd recommend bringing a stroller that her car seat can fit into and gate check them both. Then I didn't worry about the car seat making it to the destination. I did buy a special bag that fit the car seat to protect it a little more, but it's not required.
It is a little tricky to juggle things through security but I found people very willing to help fold the stroller and patient that I was taking a little longer. Once they told us we could go to a special checkpoint for wheelchairs that wasn't busy at all.
A pacifier was all I used for ear popping. She mostly wanted to look around and see what was going on at first, but settled after brief fussiness and slept most of the 3 hour flight. I'd recommend feeding and changing her before you board, since the bathrooms could be a challenge to change them in. If she gets fussy on the plane don't be afraid to feed her a little more for the sanity of people on the plane not used to crying babies.
Get up and walk the asiles if you need to...request an asile seat in the back of the plane if you can so it's easy to get up and you don't have to walk through the whole plane if you want to duck in the bathroom to settle her. Bring a little toy she enjoys to distract her, but the people watching for them is great.
You might want to bring Tylenol, saline nasal spray, etc. but make sure to check it in your baggage now with the new regulations, in case she gets stuffy or picks up something from traveling so you don't have to rush out and get it.
Otherwise enjoy your trip! This age is the easiest to travel with because they're not moving around too much yet and if your breastfeeding the meals are self-contained....even though it doesn't necessarily feel easy at the time. Good luck!