Hi Jessica!
Thank you for bringing your question to the Disney Parks Moms Panel. I actually experienced this myself about a month ago when I took my 11 month old to Walt Disney World for his first haircut!
Disney's Magical Express buses are large motor coaches and car seats are not necessary. In my experience, if you bring a car seat the driver will actually store it under the bus and they are
not permitted in the passenger cabin. They do have seat belts on the bus so the children can either sit in their own seats buckled or on your lap for the ride. For such tiny humans, kiddos can require a lot of stuff and one of my favorite things about staying on property means we don't need to travel with a car seat!
The ride takes about 30 minutes from the time you leave Orlando International Airport to the time you'll arrive at the first resort, some buses will stop at more than one. Luckily they usually show entertaining videos of classic Disney cartoons, bits on some of the newest attractions at Walt Disney World or even fun Disney trivia!
Please let me know if you have any other questions and I hope y'all have a magical trip!
-Lindsey ºOº