Ok, time for a school physics lesson. KE=0.5MV(sq). When you land, brakes are used to bleed off Kinetic Energy (KE). M is Mass - of the aircraft in this case and Vsq) is the square of the velocity - of the aircraft in this case. And so, operationsair, what we learn is that, in fact, approach velocity has a much bigger impact than aircraft weight on aircraft landing performance. Given that a bigger aircraft such as the A318 usually has a bigger wing and thus "more" (or bigger) high-lift devices and spoilers, it's approach speed will be relatively low. Mass has an impact (no pun intended), sure it does, but KE varies with the square of speed.... Aircraft brakes are also dimensioned for the size, weight and speed of the aircraft... as saman says, all things are definitely not equal. I don't really know the capabilities of the A318 in much detail but I'm guessing it has much bigger brakes than an RJ100. Oh, and it has thrust reversers, too......