Originally Posted by ASELdriver

I would also never book the window unless the aisle was my travel companion. With the seat in front reclined, there is no polite way to climb over a stranger sleeping in the aisle seat.

My preference for solo travel: pick an aisle seat in the center section. If loads are light, you are more likely to have a free seat beside you. If the middle seats in your row are both occupied and you are sleeping, but the people on the other side are awake, then both middle seat people will likely ask the other aisle person to let them out rather than wake you up.