Am a daily exercise person, but when I fly I take a day or 2 off. Nothing wrong it rests the body. So I really don't understand the need to have a treadmill. And what happens if you want to use it and someone is already on it? Do you carry your running shoes with you?

Once while waiting for the gate, I saw a man do some stretching and fast walking. Why can't the OP do the same? Going between people is like a slalom walk.