I traveled back in September with my 8 week old and then again when she was 18 weeks. She did great every time. The first time, I took my Boppy pillow with me and nursed her on the take off and landings and she just slept the whole rest of the time. People didn't even realize that there was a baby behind them! The second time, I didn't take the pillow, but asked for a couple of the airplane pillows and did the same thing with the nursing. The sucking helps their ears adjust.
I have to admit though that I planned out everything before I left. The first time I travelled with my husband but we had everything so planned out that I felt very confident to travel with her by myself. By planned, I mean, I even planned exactly when I would take her out of the carseat and stroller and how I would carry her on the plane! And remember to give yourself a lot of time. If you take a carseat and/or stroller on the plane, you can get it through security, but you have to take it all apart (baby comes out, all bags off the stroller, stroller folds up and goes through the x-ray machine and the carseat goes through separately, you carry baby through screening). and then when you get on the plane, if you don't already know you have a seat empty next to you, ask the flight attendants if you can get one if one comes available. that really helps to not have all the stuff on the floor and having to keep leaning over. I found the flight attendants to be very helpful with this. OH, and changing diapers is a trick on an airplane because the bathrooms are not very, let's say, big. Just be ready for that!
Okay, now that you have a book about flying with infants...! Hope it's helpful! Good luck!