Bah they could at least be twice as efficient, they forgot the ceiling. They could easily fit twice as many people in if the attach seats to the roof that mirror the seats on the floor. That way not only do you get rampant butt touching, but also get something vaguely resembling the numbers 6 and 9 too!
I'm sure it all would go real well if the TSA takes things to the final level when it comes to what you can board the plane wearing.