Question: Taking several notable real life inspirations from the animal kingdom I like to design a realistic Dragon towering any creature ever lived but has a nasty habit of generating sonic boom every where in its wake. What are the prerequisites my Dragon have to evolve in order to attain supersonic flight? 

I think it's must have close to a mammal blood circulation to supply ample oxygen to its already effective muscular system and is warm blooded like a cheetahs to give it energy for sudden rush of adrenaline, a crocodiles eyelids to cover it eyes, and so on. My concern is that this colossal winged breast would be too heavy and its skeletal structure have to be augmented naturally through evolution but I have no clues how any animal can survive unhurt after performing such a earth shattering feat any ideas? No tech pls and absolutely no thunderpants!

Answer: 
I was going to post this as a comment on @Zibbobz's answer, however it kind of grew to being its own answer.

If there was some local fauna which was kind of like kelp. With pockets of hydrogen gas to help hold it's self up. The plant would have evolved this to help them scatter their seeds or pollen over a very large area. 

When the dragon wants to go hunting it grabs hold of lots of these. Cuts them free of the ground and floats up, up and away. These plants will have evolved to have very stretchy gas sacks so they can reach higher altitudes. (a normal weather balloon can stretch four times its size during flight[1](http://www.diyspaceexploration.com/introduction-to-high-altitude-balloons/)) During the early phase of the flight the dragon takes many deep breaths to oxygenate its blood and then holds its breath once it passes out of the range where it can breath. Whales can hold their breath for up to 90 minutes.

Once the dragon is high enough or the balloon/kelp pops it drops down in a very stream lined shape with its wings folded back. It is still holding its breath. Here it will break the sound barrier. The pray it is falling on will not see or hear it coming. The pray is going to have to give it a huge amount of energy. This has to feed a dragon after all.

As the dragon needs to slow down it first goes from noes down to nose level then slowly expands its wings. Hopefully managing to glide out of the fall before it splatters its self into the ground.

The highly flammable plants may be a problem with this plan. Maybe need to explain that the plants seeds can be activated by fire and thus why they are around fire breathing dragons. We are trying to deal with big dragons, some amount of hand waving is required to deal with the square/cubed law.
Taking the speed of a perigrine falcon as 1/3rd the speed of sound.

We know that the force of acceleration is proportional to mass.

We know that the force opposing this (air resistance) is proportional to surface area and the square of velocity.

We can rearrange those to say that velocity is proportional to SQRT(mass/surface area).

We can say that mass is proportional to density and wingspan^3.

We can say that surface area is proportional to wingspan^2.

So velocity =k x SQRT(density x wingspan).

We can define density to be density(any animal) = density(peregrine falcon) x y.

using symbols v = p(falcon) x y.

Where y is the density of the animal divided by density of a falcon.

So v = k x SQRT(pyw).

For a peregrine falcon, v = 1/3 speed of sound = 113 m/s. Where; p=1,w =1.

113 = k x SQRT(1).

So k = 1.

For a dragon:

v = 113 SQRT(xw).

Lets set w = 30 meters, and density double that of a falcon, x=2.

v = 113 SQRT(60) = 875 = nearly triple that of sound.

Assuming you have solved the problem of how such a big and heavy animal flies, then getting them to dive much faster than sound is trivial.

The bigger they are, the faster they fall.