I would try things she can suck or chew/swallow, it is the swallow motion that relieves the pressure in the ears on, even if it is a finger. With DD1 we used a boob or dummy, for taking off and if she was awake landing, she was around the 12 month mark, and then at 18 months we used the dummy or a bottle of water.

We are flying with both girls soon and will probably give DD2 something to chew/suck, we have just ditched the dummy, and DD2 will get the boob, she isn't a dummy girl, only occassionally.

Goodluck and I hope it all goes smoothly for you all xxoo