No, simply boarding from back to front, with assigned seats, is not the fastest way to board a plane. There have been several studies done on this by efficiency experts, and controlled experiments, and it turned out that giving people the freedom to choose their own seats once they are on the plane, with no assigned seats, gives them a strong incentive to: (a) get as close to the front of the line as they can (even if it means paying more to be in boarding group A); (b) choose a seat based on all factors in place at the time, including avoiding those people in front of them putting lots of carry ons in overhead storage; and (c) getting their butts in a seat quickly. As I said, the mathematics is fascinating - a branch of chaos theory dealing with spontaneous order. Just like economic markets, the order which spontaneously arises from multiple individual choices, each person considering his or her own preferences as well as the conduct of the other people around them, is most often more efficient than the order imposed by rules created from above. As for paying extra to get in Boarding Group A, and getting first pick of a seat, that's purely a matter of personal choice. Every seat on the plane is going to the same destination and arriving at the same time. If you want the cheapest ticket, take a middle seat in Row 28 and be happy. If picking your own seat is important enough to you, well, pay for the priviledge. No one is holding a gun to your head either way.