Capt. L. Tocher wrote:
That was actually one of my main complaints about Trek: the ships are so damn slow. Really, in space, there's nothing to weigh them down. If the pilot's skilled enough, it should be able to fly around like a jet fighter. Perhaps even more agile. Never made sense to me having them float by like sluggish boats stuck in mud.
Mass. The larger a ship, the more mass it has, the more energy is needed to move and maneuver it.
Christopher Bennett has a nice explanation for Trek's fast-moving huge ships in his Ex Machina
: even under impulse power the ships are enveloped in a warp field that reduces the ships' inertial mass to a fraction of what it actually is.