The USS Enterprise's role in the 23rd century Starfleet has been retconned in Star Trek: Strange New Worlds. The highly-anticipated Star Trek on Paramount+ series is a prequel set aboard the Starship Enterprise commanded by Captain Christopher Pike (Anson Mount). With Pike's Number One, Lt. Una Chin-Riley (Rebecca Romijn), and Science Officer Lt. Spock (Ethan Peck) at his side, Strange New Worlds will chronicle the voyages of the Enterprise in the years before Captain James T. Kirk (William Shatner) takes command of the legendary starship, which is now being called "the flagship" of Starfleet.
In Star Trek: The Original Series, Kirk's Enterprise embarked on a historic five-year mission to explore deep space and make contact with new lifeforms and new civilizations. However, the Enterprise was never called the "flagship" of the United Federation of Planets in TOS. Kirk's vessel was just one of numerous starships serving in Starfleet, although the Enterprise NCC-1701 and 1701-A in the Star Trek movies performed many important roles during the 23rd-centry era. But it wouldn't be until Star Trek: The Next Generation in the 24th century when Captain Jean-Luc Picard's USS Enterprise-D would be formally recognized as the flagship of the Federation. It was implied that this was because of the Enterprise's storied legacy that began with Kirk's (and Pike's) voyages.
In a new promo video for Star Trek: Strange New Worlds, Dr. M'Benga (Babs Olusanmokun) refers to himself as "Chief Medical Officer in the flagship of Starfleet." This is the first time the 23rd century USS Enterprise has been referred to as the flagship in Star Trek's Prime Timeline and it formally changes the Enterprise's role in Starfleet during this era. After all, if Pike's Enterprise in Strange New Worlds is Starfleet's flagship, it stands to reason Kirk's will be as well. This does track with the roles Kirk's Enterprise often played in the 23rd century, even if TOS never calls the Enterprise the flagship. But Strange New Worlds' retcon now changes the context of Kirk's Enterprise in Star Trek: The Original Series. Although, by the Star Trek movies, the USS Enterprise has aged and lost its luster, and Starfleet wanted it mothballed and replaced with the USS Excelsior, which boasted transwarp drive.
The impetus for redefining Pike's Enterprise in Strange New Worlds as the flagship of Starfleet may have begun with J.J. Abrams' 2009 Star Trek movie. In the film's main story, which is set in the alternate Kelvin timeline in 2258, the USS Enterprise was called the Federation's flagship by virtue of being Starfleet's newest and most powerful starship. The Enterprise in Star Trek 2009 was launched under the command of Captain Christopher Pike (Bruce Greenwood), although James T. Kirk (Chris Pine) became the Enterprise's Captain by the end of the film. Calling the Enterprise the flagship of the Federation in Star Trek 2009 was one of the film's numerous changes that were afforded to them by creating an alternate timeline.
Of course, much has changed since Star Trek: The Next Generation christened the Enterprise-D as the Federation flagship, in part, to honor the legacy of Kirk's starship. Star Trek: Enterprise launched in 2001 and retconned the 22nd-century NX-01 Enterprise led by Captain Jonathan Archer (Scott Bakula) as the first starship of that name to explore the galaxy. This placed Kirk's Enterprise as part of a lineage instead of the creator of it. Even though it was essentially the flagship of Starfleet, the Enterprise NX-01 was not formally called so. With Star Trek: Strange New Worlds, the Enterprise is now officially recognized as the flagship of Starfleet in the 23rd century and this recontextualizes the role of Kirk's ship and the legacy honored by Picard's Enterprise-D as well.
Star Trek: Strange New Worlds premieres Thursday, May 5, 2022, on Paramount+.