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.
A creature meeting your size, speed, and strength requirements would have to be composed of extremely lightweight tissues, most notably including the skeleton (which must be able to handle the physical stresses of accelerating to supersonic speeds rapidly) and muscles (which must be able to convert the creature's biochemical or magical energies into mechanical energy efficiently, rapidly, and at high volume).

The most "realistic" way I could imagine all of these requirements being satisfied is if your dragon looks like a blimp: a giant sack of air that moves short distances by flapping its wings, and naturally floats in the air because its body density is about equal to the surrounding air density. Such a creature might achieve supersonic speeds by rapidy forcing most of the air in its body cavity through a small opening to create jet propulsion. This would also cause the creature to deflate to a narrow, streamlined shape that's more aerodynamic for long, straight flight paths.

We could go into further technical detail, but as you can see the result is a bit ridiculous. Really what I'm saying is you need a fart dragon.