I remember watching this show around 20 years ago, likely on a children's cartoon channel (probably Cartoon Network, Toonami or Fox Kids) so it could well be a 90s cartoon or a re-run. Don't remember much of the story other than they would break out this giant robot to fight crime or whatever the disaster of the day was. I remember the robot itself being pretty bland compared to other anime styles but still quite cool and sleek and could fly using rockets in its feet. It was all black from what I can remember and looked very much like someone from a SWAT team or the police (possibly with a visor). Haven't been able to place the show whatsoever and it's really nagging at me...
Gigantor the space age robot? I know it had a sequel to the old sixties series. It was used as a 'guardian of the peace' and had rockets to fly with
YouTube link to the sequel series, possibly what you viewed, he can be seen flying about five seconds into the intro
Perhaps its the Patlabor series?
It fits the data of being a robot/mecha to fight crime or disasters.
It does not fit in the fact this carry a people inside (but can be remote controlled) and as far as I remember it cant fly.