Even on the WDW busses it's a challenge depending on where I'm tied down. She can't lay in front of me due to the tie downs and if there's a chair in front of me there's no seat for her to go under. I usually don't have her go under a seat anyway as she gets kicked and it's filthy under the seats, plus she can't be close enough to me to help in the event that I need her. It's horrible when the bus is packed with standing room only. She's been hit by purses and diaper bags, kicked by children, poked and stepped on, poor girl.---Kathy