Hi John,
The mass of the plane is not held up by the engines but by the wings, firstly! No no, stupid Andy, you know that...... *smacks forehead* but of course the engines give the wings the relative airflow for lift. So: I've heard one or two pilots mention that the different philosophy of design between A/B involves Airbus using "just enough" thrust to get off the ground but greater wing for cruising, and Boeing with lots and lots of thrust but "just enough" wing for cruising. Obviously I'm sure it's far more than "just enough" but you get the picture.
No idea how that works w.r.t. maintaining the same cruise speed though.
Andy