Answer:
Repetition creates a rhythm that emphasizes important ideas. This excerpt is repeated several times. How does this repetition affect the epic? It emphasizes the length of Gilgamesh's and Enkidu's journey.
The correct version of these two sentences when combined is:
When we were in Europe on vacation, we usually flew on airplanes: however, sometimes we took the train.
We apply the semi-colon to indicate that they have different ideas, and that they are clauses being joined into one sentence.