Spoilers for Thor: Ragnarok and Avengers: Infinity War follow!
In the moments which saw Thor declare to his brother it was time to head back to Earth, his ship with the remaining Asgardians was overshadowed by another. That ship is now confirmed to be Thanos' ship, the Sanctuary-2.
The final pages for the Thor: Ragnarok script calls for Thor and Loki looking through the window after their dialogue. "They see -- the massive form of Sanctuary-2, Thanos' Warship approaching," the script said.
"A wider view allows us to see all of Sanctuary-2, dwarfing the Ark in size," the script concludes.
Heading into Avengers: Infinity War, Thor, Loki, Bruce Banner, Korg, and their pals will be the first to encounter the Mad Titan, it appears. This makes Thor: Ragnarok a direct lead into Avengers: Infinity War, barring any appearances from the cosmic characters in the earth-based Black Panther film.
The full script for Thor: Ragnarok has been made available by Disney for 2017 awards considerations.
Avengers: Infinity War opens in theaters on May 4, 2018. Other upcoming Marvel Cinematic Universe movies include Black Panther on February 16, 2018, Ant-Man and the Wasp on July 6, 2018, Captain Marvel on March 8, 2019, the fourth Avengers movie on May 3, 2019, the sequel to Spider-Man: Homecoming on July 5, 2019, and Guardians of the Galaxy Vol. 3 in 2020.