The Titanic sailed from Southampton, not London.
The Titanic is sailing with smoke coming from all four smoke stacks - one of the smoke stacks on the Titanic was fake and would not produce any smoke.
When the 3 travel back to 1803 the American flag has only 15 stars. 1803 started off with 16 states and then added the 17th that year.
The Titanic struck the iceberg in the middle of the night(at 11:55 pm), not during dinner, as portrayed in this episode.
Ernest Hemingway in 1921 Paris did not have gray hair. He had dark hair. He also did not have a beard in 1921. He was sporting a clean shaving look. He didn't grow a mustache until he 40's. Also Hemingway didn't grow his trademark beard that people think of him today until he was almost 50 in Cuba. Hemingway was born on July 21, 1899. So in 1921 he would've been 22.
Hemingway shot himself and committed suicide in 1961 in Ketchum, Idaho. Not in 1921 Paris. However, he also did not meet Brian, who clearly changed the course of history as we know it, causing Hemingway to kill himself there and then by pestering him "about the craft".
The Louisiana Purchase gag makes no sense. None of the states named existed at the time, not even Louisiana itself, which only formally became a "territory" after the purchase.
It makes no sense to immediately assume Harpington was the ancestor of Chris' history teacher just because he had the same name.
It makes no sense that the time travelers fail to change the present by killing Ivan Pavlov. His theory of classical conditioning has been used in various real-world applications, especially mental health but also education, advertising, pet training, placebos, and taste aversions. Clearly, killing him would have put back all of these fields and more for decades which would have had the most profound impact on the course of history and the present.
The correct song title for the sheet music that Stewie gives to the ship's band is simply "Danger Zone", not "Highway to the Danger Zone" as both he and Brian state. (The song was originally performed by Kenny Loggins and is available on the Top Gun(1986) soundtrack)