I’ve flown by myself with DD a few times prior to her turning 1. My mom took her on a plane by herself too. It can suck, to be completely honest, but at least you’ll have help. Plus, it’ll be a lot better than driving.
My suggestions are:
1. Pack extremely light. Start far in advance, lay out everything you want to take, cut it in half, repeat. Bring one or two small toys at the most– she’ll be getting so much attention that she really doesn’t need the toys. If she gets bored, she can tear pages in the Sky Mall catalog or look out the plane window. She can rewear outfits too, just find a hotel with laundry or a family member’s house.
2. Get to the airport extra early. I really think that baby’s can sense stress and getting through airport security with a fussy kid when it’s busy is extremely stressful. They make you take the baby out, collapse the stroller, test any breastmilk/mixed formula you bring along. Plus, you’ll want to be one of the first people on the plane so that you can get settled. If you’re there on-time/early, they’ll let you board with the first group.
3. As soon as you get on the plane, get the essentials out and put them in the back pocket of the seat in front of you. The seats on planes have gotten so small and it is brutal to try to hold a baby and dig through the diaper bag while in the air. Put the special toy, mixed up bottles, etc. in the pocket, so you can grab easily.
4. As the plane takes off, make sure your baby is eating. This helps to with ear pressure. Have you seen those fruit to go things that kids can suck on? If you have started adding food to her diet, look for an oatmeal or applesauce one of those. My daughter was too distracted to drink her bottle on one of her trips, but she sucked on the fruit to go thing instead and it really helped with not causing her pain.
5. Bring Tylenol. Depending on how long of a day she’s going to have, she may get a headache/some other ailment just like any of us would. Also, with all the germs in the recirculated air on planes, you’ll probably need it during your trip too.
6. During transfers, watch for the giant family restroom. You can lay her out on the changing table so she can stretch and wash out bottles. Consider bringing one of those travel size dish soaps so that you don’t have to bring so many bottles.
Finally, just relax about the whole thing (so easy to say, right?). When it comes down to it, every passenger (whether they realize it or not) annoyed the crap out of some other individual when they were a kid. So if your daughter screams and screams or is a perfect angel, just go with the flow. You being calm and relaxed will do more benefit than any other types of preparations.
Good luck! I bet the great grandparents will love meeting her!