How are physical therapy exercises on a plane undertaken?

Seated or standing. What type of injury are you rehabilitating. There are seated isometric exercises for the neck and back as well as some to prevent circulatory issues.There are simple standing stretches you could do in the aisle for back or leg pain.
Not much room. There isn't a lot of room on a a plane. In your seat you can do neck stretching and range of motion exercises. You can do a modified pelvic tilt. You can stand in the bulkhead and bend forward to stretch. In your seat you can move your foot and ankle to stretch calf. Remember to get up and walk in the aisle to keep blood from pooling in your legs to prevent clots.