What? That's the Benatar, the Guardians second ship after the Milano was crashed in Vol. 2, which is used repeatedly throughout Infinity War and Endgame
The Guardians used it to get to Titan in IW
Nebula arrives in a Sakaaran Necrocraft after escaping Thanos' ship
Tony and Nebula are adrift in the Benatar after the battle on Titan, the fuel cells were damaged
Captain Marvel brings the ship back to Avengers HQ
The team goes after Thanos at the Garden
In the interim 5 years we hear that Nebula and Rocket are off helping mopping up various calamities in space (as is Captain Marvel, Okoye, and Rhodey) and we see them return to HQ (blowing away Lang's tacos) after the team is brought back together for the time heist
Rocket and Hulk fly to New Asgard to get Thor
For the Time Heist Hawkeye takes the ship (shrunken) to Morag
On Morag they separate the Pod from the main ship
Hawkeye and Widow fly to Vormir
Hawkeye brings it back on the return time jump, presumably (he weakly promised Rocket he would), and the Guardians are back on their ship at the end