51¶¯Âþ

Stretch jumbo jets are hard to manoeuvre at airports and need longer runways.
So Boeing is patenting (EP 987 177) a jet with an extra upper deck at the rear
so that airlines can cram more passengers into their aircraft without making
them too long. To meet the safety regulations on emergency exits, which don’t
allow exits above the wings, the new plane will be built like a camel, with two
humps and a dip in the middle over the wing. The dip is simply a connecting
corridor, so it needs no emergency exits. Boeing says that the two-hump design
unexpectedly decreases drag, compensating for the extra weight and boosting
cruising speed.