Third Nacelle wrote:
I wouldn't call the NX-01 "modern." It would probably look very antiquated to Kirk & Spock. Aesthetic sensibilities change over time.
I prefer to think of the time travel in First Contact to be the predestination kind of time travel, but even if it is an alternate timeline, it's one that becomes identical to the prime timeline by the events of Pegasus.
They did a good job on the internal sets of NX-01, making it appear about a century before Kirk & Spock, but the exterior of the ship itself is another story, it's hard to argue that design is 100 years before the 1701 as seen in the original series.
Unless the FC-altered NX-01 timeline led to J.J.'s alternate timeline, in which case J.J.'s 1701 looks more like an evolution of NX-01.