I remember our task groups to travel at about 45mph - which is about 39 knots(using statute miles, since WW2 didn't use nautical miles IIRC). That's an entire fleet travelling faster than an average anti-sub destroyer at its attack run - and that's only when running straight, too. When the ships begin to turn and take up new positions they travel even faster.
IMO, there should be a "cruise mode" and "combat mode" the fleet commander can set. In the "cruise mode", the ships will travel as it is (for sake of gameplay), but it won't be able to launch planes or use any ship guns other than AA guns(20mm, 40mm, 5", etc..)
In "combat mode", the ships should slow down to about 20knots(23mph (statute miles)). The guns can be used and planes can be launched at this mode.
A separate "emergency maneuvers" button would be added to the control box when the fleet is in combat mode, which the entire fleet goes into a preset evasive maneuver such as "knuckle right/left", the ships accelerating to full speed, turning as hard as they can, so the fleet commander doesn't have to switch to "cruise mode" manually and halt ship bombardment or plane launching. However, these evasives would have a slow moving ship accelerate at a reasonable level, so it would be a lot less effective than our current fleet breaking left or right in insane circles.
Changing between "cruise mode" and "combat mode" would also take a certain bit of time, since the ships all have to accelerate or slow down and crews/pilots go to "battle stations". Maybe something like a 2 minute interval.