I decided to do some illustrations of uniforms (Command, Science, Security/Engineering, and Cadet) that could be used in the 100 years between the two series. As space travel became safer and more mainstream, the uniforms changed from the utility jumpsuits of Enterprise to more relaxed ones seen in The Original Series
In this one, the Enterprise jumpsuits are now a two piece uniform with a colored undershirt.
In this one, the undershirt becomes the primary uniform. The blue jacket top becomes sort of a bomber jacket (like what kirk and scotty wore in some of the movies) and is not commonly worn.
In this one, you can see the progression towards The Original Series style of uniforms.
Then all you have to do is make the pants black, lose the shoulder strips, and add a black under shirt and you have the TOS uniforms
Let me know what you all think!
In this one, the Enterprise jumpsuits are now a two piece uniform with a colored undershirt.

In this one, the undershirt becomes the primary uniform. The blue jacket top becomes sort of a bomber jacket (like what kirk and scotty wore in some of the movies) and is not commonly worn.

In this one, you can see the progression towards The Original Series style of uniforms.

Then all you have to do is make the pants black, lose the shoulder strips, and add a black under shirt and you have the TOS uniforms
Let me know what you all think!