If that's your goal, there's a place you're likely to sleep better than any other: a window seat. Specifically, pick a window seat on the left side of the aircraft. These seats are usually off-center, making leaning up against the side of the plane more comfortable.

For the vast majority of travelers, the window seat is the undisputed best choice for sleeping. Its primary advantage is the "lean factor"—you can rest your head against the cabin wall, providing much-needed neck support that an aisle seat lacks. Furthermore, sitting by the window ensures that you won't be disturbed by seatmates needing to use the restroom or by the beverage cart and passengers passing in the aisle. To maximize sleep quality, try to choose a window seat away from the galleys and lavatories to avoid noise and light pollution. If you are on a long-haul flight, a window seat in the "bulkhead" row can offer extra legroom, though you lose the ability to store a personal item under the seat, which some find inconvenient for accessing sleep masks or pillows.