[quote=Veratisu]
Where did you get delta flyers
[/quote]

Paid for them on the Cryptic Store.

I assume you mean in continuity. Well, STO follows the events of Star Trek in the year 2409, 30 years after the events of Nemesis and 22 after the Hobus Incident (Where Spock tried and failed to save Romulus. And then was sucked into a shitty movie series.) With Romulus Destroyed and Praetor (Emperoress) Denatra killed, the Romulan Empire fell into infighting, with everybody that had some semblance of power trying to set themselves up as the new Praetor. Most of them were either ignored or assassinated. Then the Klingons decided to take back the territories that they had lost during their war with the Romulans and, once again, the Khitomer Accords (Federation-Klingon Peace Treaty) broke down as the Federation took a stance against the Klingons slaughtering defenseless civilians. Eventually, using her newly acquired Herojin Allies, Sela took control of the Tal-Shiar and used her military strength to rally the rest of the disconnected Romulan states into a new Romulan Empire, where the Tal-Shiar had full control... Needless to say, an empire being ruled by a shady, secret operations, military bureau wasn't exactly the nicest place to live. Sela poured the entire wealth of the empire into rebuilding their fleets and managed to push the Klingons out of their territory.

So, now Sela had unquestionable control of the Romulan Empire and they were flat broke... So, she did what all great dictators do and got her boot-boys to start plundering the people. Everybody in the Empire lived in fear of the Tal-Shiar, either pay them everything you own, or they kill you. Finally, the inevitable rebellion happened. The Romulan people, lead by the remnants of the Reunification movement (Romulans and Vulcans used to be one species, the Reunification movement wanted to bring the two races together again) Thanks to funding from both the Federation and Klingons (In return for access to some of the Romulans Technologies), and with the Remans joining them, the Rebels managed to amass enough forces to splinter off and create their own Republic. The Republic is now in a prime location for expansion, the Klingons are protecting their boarders as part of their treaty, and the Federation are granting them ships in return for assistance during operations by Starfleet.

As far as where the Delta Flyers come from, I think that the canonical answer is that they are standard issue for any ship that is a member of Battlegroup Omega (A joint Federation, Klingon and Romulan taskforce built to deal with Borg incursions into the Alpha Quadrant.)

[quote=VG Spartan91]
i agree in the timeline the voyager crew would not have even comeback yet
[/quote]

Voyager returned home in 2378, this ship is from 2409, 31 years later.