Hello Nicole and thanks for bringing such an important question to the Disney Parks Moms Panel.
I've had a good think about your query and I don't believe that there are any attractions at Walt Disney World Resort which require Guests to remove their foot wear before riding or even require any particular style of shoe.
Having said that, if I happen to be wearing flip-flops when I ride my favourite attraction -
Soarin' I usually remove my flip-flops and stow them safely away in the provided net storage compartment.
Cast Members at Walt Disney World Resort are simply
Wild About Safety and can be consulted if you have any concerns about appropriate footwear before entering an attraction queue.
My top tip would be to wear whatever you are most comfortable in because you'll be on your feet a lot whilst enjoying everything on offer at the Disney Parks!
If I can sprinkle any extra pixie dust onto your upcoming Walt Disney World Resort vacation please pop back to ask me another question.
Have a great Disney day.
~ Jane