I've actually have done this recently, it was a domestic flight with JetBlue to and from MCO but I didn't have any issues. They gave me the underseat basket to put in the overhead bin and the rollator was gate checked. I use a foldable cane which I stow in the basket and it made matters a lot easier. Just as a caution I printed out my own label with my name and cellphone # just in case. Hope this helps.