J.P.
If you have a front carrier, like an Ergo, take it!
Nurse during take off (and landing), let her fall asleep nursing if need be. Let her rip up the magazine if that is what she wants to do, and screw the schedule while flying. :) Also, get a jar of ear plugs for neighbors, just in case! Just go with the flow, and don't stress too much. She will feel your stress.
Oh, and change her in a corner of the airport before boarding, so that you don't have to do it on the plane (try to avoid that if possible), and if she is in a front carrier, you should be able to go yourself before take off too.
Check EVERYTHING you don't need. If you can, only go through security (if she is in a front carrier with no metal, you don't have to take her off) with her and a diaper bag.