book the flight, i choose an aisle seat toward the back of the plane. the front tends to fill up faster, and the back last because passengers generally want to get off quickly. i also aim for a row where the middle seat is empty, but where the window or aisle is already booked. groups of two or more will have to look elsewhere. and typically passengers traveling alone will pick a middle seat only if nothing else is available.
on international flights, where the planes are usually bigger, i also stick to the center section. those middle seats are the farthest from the window, which to others can feel the 