Trust me many years back I've seen an F-16 over sargodha at a very high speed Must be over Mach 1.2-3 atleast, as it was giving a long smoke trail at quite a height. It was reducing its speed by turning left not more than 5-10 degrees and one could easily assume if it banked more on that speed it will loose control,it took more than a minute in that position and then lost it's supersonic speed. Then it started to dive a bit and started taking turns in a circle and then again dive to loose altitude and then again turn in a circle as it cannot loose alt in one dive. It came over the base and landed. I was in 16 block area ( high roof house) Sargodha and could clearly see it going landing towards the runway. So Iam sure at supersonic speeds dog fights are not done as jets can't menouver like they do. Mach speeds r just to run back when they do their job in enemy territory. Mach 1.6 or Mach 2.0 are rarely achieved in routine practice.