https://en.wikipedia.org/wiki/Drag-divergence_Mach_number#:~....
[Increasing Mach Number] can cause the drag coefficient to rise to more than ten times its low-speed value.
I only know this because of a number of fluid-dynamics courses that are only required for Mechanical and Aeronautical engineering majors. Barely anyone else is expected to know this information. Mach numbers represent fluid-flow discontinuities. If there is fluid flow in a varying inner-diameter tube and there is a Mach number change from <1 -> >1 at any point in the tube, as long as the Mach discontinuity is there, fluid flow characteristics before and after the discontinuity are decoupled from each other, they no longer influence each other if the Mach discontinuity is present.
I would imagine drag increases linearly or exponentially with speed - not as a step function once you cross the sound barrier.
Or are you saying because it's going to be flying twice as fast?