You'd rock too much. Your space would intersect with the space of another person. My Texas-sized body just doesn't fit into those coach seats. My shoulders cram into my neck. My arms bow.
Space is invaded.
I look out the window. I think from now on I'm going to spring for the bucks and go first class. I got a chance to catch up on my reading. According to Fortune, Lee Iacocca flunked retirement. A riveting story.