Do you have a wrap or something to where you can wear her?
I had LO in a Moby wrap and it made everything a lot easier.
Nurse, offer a bottle or have her suck on a pacifier particularly during take off and landing. It helps with the pressure.
LO slept the entire time. I think most babies that little do. They are surprisingly a lot easier that young than when they get older. I am beyond terrified to fly with LO now lol