Well the key here is the hexagon. War Rocket ship movement is based on 60 degree rotations, and each corner of a hexagon is 60 degrees -- stay with me, this is just what was flowing through my little brain -- Either the map or the bases would provide you with a hexagon to reference your turns to, but I didn't want either. Eureka! Many ship games use a turn template; Hell's bells! How easy is that?!
Anyway, so I will make myself a turn template with 60 degree angles. There are a couple possibities: You can make the "border" of a hex (choose your own material) that wraps around your ship (since the ship "rotates" instead of "turns"), or you could simply cut a hexagon out of your preferred material (I have some leftover plasticard.) I prefer the second method because the template can be made thin enough to slip under the base of your rocket ships, and is less fragile. You can also paint up some wicked-cool art on it if you like.
With a turn -- no, let's call it a rotation template, your bases can be whatever shape and material you want. I prefer the soft edge of a round display base, in which case I'll have to use the orientation of the model itself when I rotate it; or I can use square bases with the ship pointing toward one side. This way, I can simply line the side of the base up with the edge of my rotation template.
Note: Here's a method for drawing a hexagon using a compass and a straight edge, to help get you started making your own rotation template. Thank God for geometry. Or thank the Greeks, if you prefer :)
Final thought: War Rocket ships already come with hexagonal bases, but don't overlook the beauty of some of the space mats that are offered. A rotation template brings practicality to the game, but a space mat adds more art. There's nothing wrong with a little frivolity.