DD is just a little older than your son, turned 2 last May. She does go to daycare, however her age isn't required to wear masks so that has not helped in regard to getting her practice but she does see the older kids in masks as well as all of the staff.
She is still learning to leave masks alone but she has shown willingness, and I think a lot of it is how we've gone about it with her. We let her know about the trip early on and we told her that Mickey says she has to wear her mask on the airplane to come visit and when we're there having fun. We found a few recent ride videos of things she would be interested (Ariel, Haunted Mansion, and Barnstormer off the top of my head) where the guests and staff are wearing masks and she will sometimes ask for a mask just sitting at home when she wants to watch those videos.
She is also enrolled in a swim class where the staff are all masked and while we don't go out all the time or during crowded times we do still have errands to run and we make a point of doing them as a family so that she sees DW and I both in them, as well as employees, customers, other kids, etc.
DW was recently in a Walgreens to get a flu shot and DD had her mask on but it was slipping down. DW told me that another child went by with their family and the mask was on correctly so then our DD pulled her mask back up over her nose on her own. And yes, we did get some kids patterned masks for her so they are more interesting, too.
We are still working on it ourselves but if you asked my daughter right now what we have to do to get on an airplane and/or go to Disney she would say put on our masks. I'd love for it to not be necessary but I'm realistic. Our trip is coming up in March so definitely getting anxious about making sure she is really ready for this coming so soon. Good luck, hope some of that helps.