[yawaworht1978]

Can supersonic aircraft be as big as the 747 etc jumbos without much worse energy requirements?

Or does the fuel consumption rise by a factor?

I can see the Concorde had almost mach2 as top speed?

Is there another Sonic boom at mach2,3 etc?

Unless it's a fuel efficient mach3, there's not much point to it, most flying time improvements should be done on checking in and boarding, the flight itself for flights less than 2 hours in duration can't be optimized , a supersonic plane wouldn't even accelerate to top speed before it has to slow down on short flights like paris-london.

[azernik]

The boom isn't from crossing the barrier; it's from being at that high speed. A plane traveling at Mach 1.5 cross-country will leave a boom at every point along its travel

[chiph]

Going that fast requires significantly more energy. You start to worry about things like the cross section of the aircraft (which is why fast plane commonly have knife-edge wings) and smooth airflow over the fuselage.

One of the advantages of the composite construction being used by Boom is you don't have those thousands of rivets sticking out. And panel gaps. Which is why the 787 is as fuel-efficient as it is compared to traditional aluminum bodied aircraft.

[_8op6]

There is only one boom, when you cross the sound barrier.

[Reventlov]

No. See https://en.wikipedia.org/wiki/Sonic_boom