Remembering seat configs tends to be a pain unless you simply want to sardine can your passengers.
Thus... MooTools!
Config Calculator: http://ae.sirmoo.com/seatcalc.php - Based on Kitty's attempt at making a program, this uses the same concept. Simply enter the total number of seats and what percent of them you wish to occupy. It will give you 1, 2, or 3 class layouts. Merged into the seat configuration page at the bottom.
Realistic Seating Config: http://ae.sirmoo.com/seatconfig/ - Using Ogg's Seat Map Index, simply search the plane type and it will provide the configuration for you.