You will have a great time!
I have been several times just me and a child or two when DH could not go and we have had wonderful trips

I also hate flying (an understatement) but I just keep thinking about where I'm heading and how nice it will be to arrive quickly.
As far as keeping your strength up plan wisely. I would use a towncar service at the airport like Tiffany because they will help you with your bags. With Mears you are going to have to do that yourself and even with a luggage cart that can be a challenge. I can still see myself traveling with Andrew just before his 4th Bday, walking through the airport with him in the stroller, car seat, my carry on bag, pocketbook, Andrew's goodie bag for the plane... what a sight and exhausting ! LOL Make sure you take breaks everyday and don't get over tired, Andrew and I love our midday swim, he has as much fun in the pool as at the parks

afterwards we usually rest a little before we head back to the parks.
I have to say I was a tried and true Disney Commando for many years but age and 4 kids caught up to me (not to mention my family threatened never to go to WDW with me again unless I relaxed -lol) so I have discovered it is not always the quantity of rides we go on but more so the quality of the time we spend with our family during the whole Disney experience. Now Im not saying you won't find me in the front line of the rope drop at park opening, but I have learned to take the time and smell the roses now and then and everyone is happy
Plus if you are having a bad day and need a rest make sure you tell one of your DIS friends or just call us the big DIS family, well be happy to help out, Ill be there with my son and he has just turned 5.