exactly what I was thinking. on the "old" UA seats, the electronics box for the IFE was annoying but you could at least get your bag under the seat. I have one of the larger Tumi backpacks and have had no issues getting it under. Although I did not attempt to put it under the seat yesterday (went in the overhead) I did notice that there would be no way it would fit under my aisle seat on the 738 but would have under my wife's window seat... I think, anyways.