(at around 20 mins) As Phineas is on the Wright Brother's glider, a jet contrail is clearly visible in the sky above the glider.
In 1918 France, the voyagers meet actress Mary Murphy. Murphy wasn't born until 1931.
(at around 45 mins) As Jeffrey and Phineas walk along the banks of the Nile, planters holding bamboo shoots are clearly visible.
The model airplane Jeffrey picks up in the Wright brothers' workshop is a biplane design, but in this version of history, the Wright brothers do not realize they need an extra wing for additional lift until after their single wing glider crashes.
As Bogg and Jeffrey taxi to takeoff to engage the Red Baron Bogg says "Remember the Maine!" to which Jeffrey asks "Remember the what?". As an historical ace, as Bogg calls Jeffrey later in the series, and Jeffrey having demonstrated a knowledge of Teddy Roosevelt and the Spanish-American War in a later episode he should have recognized the USS Maine's place in history.
As Bogg and Jeffrey taxi to takeoff to engage the Red Baron, Bogg says "Remember the Maine!" to which Jeffrey asks "Remember the what?". As an historical ace, which Bogg calls Jeffrey later in the series, and Jeffrey having demonstrated a knowledge of Teddy Roosevelt and the Spanish-American War in a later episode he should have recognized the USS Maine's place in history.