It is not quite that simple. The mileages quoted by Dave_C are based on direct routings. An aicraft never flies in exactly a straight line (or great circle line to be precise) but has to follow routings to avoid terrain, other aircraft and world trouble spots.

Also, I'm not sure if the Airbus and Boeing figures take in to account holding and diversions. If my recollection is correct, a commercial aircraft has to carry enough full to hold for 15 minutes at the intended destination, make two approaches and then continue to an alternative destination and still have enough fuel for a 15 minute hold plus two appraoches.