Get her an MP3 player or good book to help pass the time when in the air.
Ask her about seating -- does a window add to her comfort or discomfort.
Try to avoid medication. If she is alone, last thing she needs is to be drugged as she leaves the plane. Ginger candy can help prevent air sickness as can a few medicines with minimal side effects.
Now air sickness is not the problem, but adressing it seems like you are doing something to lessen her problem.
Remind her without preaching that air travel is the safest form of long distant travel. Tell her that the pilots and crew have families and no parachutes. They will not fly if they believe conditions are dangerous.
If that doesn't help, offer her a bus ticket but warn her of long hours, bad food, few rest stops and possible undesirable fellow passengers. Also, the risk of getting hurt is much higher than flying.
Good luck. There are fear of flying books you might want to get for her.