If you can get her to the A/C without being too plastered ask if she can see the flight deck and talk to the pilots before take off. I would recommend she sits there for take off and landing - that always used to sort quite a few people out - but I'm afraid that is a thing of the past.
I always use the example of likening the A/C to your car.
Sounds stupid but....Imagine Imagine every time you get in your car to go on a journey it has been given a full MOT/Service and everything has been checked thouroughly. Your car has two of everything - steering wheel, driver, etc etc. Not only does it have all this great stuff BUT ALSO....when you start your journey someone has already sorted out your route and is watching you every step of the way and all the other cars on the road as well so no accidents occur!!!!
Again may sound stupid, but it puts it into simple terms for a lot of people and after a few moments thinking about it they are a lot calmer.
Hope this helps - and good luck.;