Back in the days when I still flew in coach (last century), I had a pretty good system going. After I boarded, I would head to the back of the plane and sit in the middle seat of the furthest back empty row. If someone came to sit in the row, I would apologize and move up to the next empty row. I almost always scored a whole row to myself and slept for the rest of the flight.

Fortunately I can sleep easily on flights. It is easier, I must admit, in first or biz.

Now days it seems like the flights are a lot further than they used to be, but if you can snag a whole row for yourself, go for it!