J.L.
Hey there! I have flown with my boys every couple of months since they were about 3 months old and have never had any problems and I usually fly solo. They are 3 & 5 years old now. I mostly fly to Maryland and its about 2-1/2 hour flight.
I would highly recommend getting a flight during nap time if you can. I give my boys pedicare right after we get sitted on the plane or right before.
They usually don't have trouble with take off; its the gradual decline right before landing. you'll start to feel it in your own ears. So I try to work a nursing or bottle around then. once I nursed too much and then when they needed to nurse, I couldn't get them interested. The pedicare opens them up and usually my kids sleep through it without drinking.
I also fly southwest so I can pick my seat or request the last row. The engine is loud back there and drowns out any crys but most importantly the noise usually puts them right out. Also, if you are in the back you can jump back and walk or rock the baby to sleep by the bathrooms, its dark back there and you can't stand up front any more (cockpit safety).
Pack books and a movie or anything else that might entertain, but I bet she sleeps. As long as your relaxed so will the baby. Good luck!