Assume I’m Superman-ish. Would there be massive building damage?
See Matrix III.
“Through”… at what altitude? Ground level? Rooftop? Low airplane?
Just above streetlight level.
Lots of broken glass. No real structural damage though (unless you actually hit a building).
You’d hurt a lot of people though. Mostly hearing-related injuries apart from all the falling glass-related stuff or to fragile folks, but you’d definitely score big damage on a collective scale.
Mach 10? Mach 100?
You’d break pretty much every window or easily shattered object you passed.
You could cause both hearing damage/injuries and injuries from people being knocked down, into buildings, etc.
At least in the US you’d break a bunch of FAA regs and laws about exceeding Mach 1 in US airspace without prior permission (which would not be given for flying through a city at streetlight-level at Mach 3 anyway).
Supersonic planes definitely break windows, but size matters. A whip cracking doesn’t break windows. Would a human-sized projectile make an intense-enough sonic boom to break windows? At what range?
What would happen if I flew through a city at Mach 3?
I did that, once.
Speeding ticket.
Mythbusters tested this with a supersonic jet (though at less than mach 3). Surprisingly even at very low altitude at supersonic speeds it was very hard to break any glass…
Jamie set up a test area filled with various glass items and products while Adam performed a flyby in an F/A-18 going supersonic. However, at flybys of 8,000, 2,000, and 500 feet (2,400, 610, and 150 m), the jet failed to break any of the glass. They then performed a series of low-altitude flybys at 200 feet (61 m), but they managed to break only a single window. Since the majority of the glass was still intact, the MythBusters declared the myth busted.
'Zactly my question.
There’s only the energy embedded in WAG 200# of person traveling at Mach 3 to impart to the passing air. Not 20,000# or 50,000# of jet.
Likewise the frontal area of air that needs to be displaced is quite different between a WAG 1’x2’ human and a fighter-sized jet, or worse yet a B-1A.
Make sure you plot your course ahead of time, otherwise you might get clotheslined by any number of random wires!
At that speed I imagine you’d look like Wile E Coyote being diced by a fence while on skis.
I was going to ask the same thing, but with a bullet instead of a bullwhip. Sadly, we have regular examples of that in some city neighborhoods.
Using Whitham’s equation for peak overpressure, an avg adult flying Mach 3 at a few meters above sea level, I came up with a peak overpressure of about 1.3 Pa and a loudness of about 100dB. So, not much damage and a pretty loud pop, but nothing crazy.
…then, since they caused insufficient damage to be entertaining-- they set off a bunch of high-powered explosives and blew everything up real good.
& the problem with that is???
Did I say there was a problem?!? 
Can you imagine the amount of mach 3 swerving that would have to be done?
BTW, what does happen when you have to make a very sharp turn at that speed?
You either hit the brakes…or you hit the breaks! 