There are 30 rows of seats on the average passenger airplane (64 rows on a 747 and around 35 on a 757). If half of the flyers preselect their seat and are granted their request, then those who have not preselected have a 1/15 chance of being in any particular row (6% probability).
On our recent trip back to the United States we had 6 different flights between the cities of Nairobi, Dubai, San Francisco, New York City, and Seattle. On each of the flights we preselected seats in the middle of the plane. On 3 of those flights (even though our seating request had been preselected) we glanced at our ticket and saw seats 64 A,B,C,D. So Sara and I and two very tired girls took the long walk past first class, past the first row of bathrooms, past coach, past the second row of bathrooms, and turned to our left just before the drink cart and stow-away seat. I mean, come-on the very back row on 3 of 6 flights (and this is not the first time) seems like more than chance.
We tried to sleep any way possible even using the lap tray to rest on but couldn't in chairs that wouldn't recline. Sara was bumped and disturbed by the doors of the restroom directly behind our seats. And of course we deboarded the airplane as the very last passengers.
It costs 4 cents to fly 1 pound 1000 miles. Amelia and Meredith weigh combined 90 lbs. That is about 1/3 that of the combined weight of an average couple 270 lbs. Amelia and Meredith pay the same fare as an adult on all domestic flights. The flight distance from Seattle to Kenya is approximately 10,000 miles. Amelia and Meredith's weight savings in cost of fuel not needed for the airlines is over $700 one way.
Do airlines intentionally seat young children at the back of the plane? Do they use online reservation age information to discriminate? Do they want these kids out of sight and out of mind in the back of the plane to retain a more professional class at the front of the plane? Is it fair when these little kids (although noisy and with a tendency to kick the chair of the passenger to the front) actually save airlines significantly in fuel costs? (Amazingly each flight could save $23 in fuel costs due to decreased weight if passengers relieved themselves before boarding.)
Has this happened to any other families with young kids or maybe I'm just imagining a conspiracy?