Answer:
Because the route taken by them was the Great Circle Route.
Explanation:
The Great Circle Route is an imaginary line believe to follow Earth's curve and provide the shortest distance between Tokyo to Los Angeles. This Great Circle Route is also known as a Geodesic. A straight line in a 2-dimensional map is different from a straight line on a 3-dimensional globe. This is the reason why the pilot takes an Arc route. Moreover, it is due to the map projection that makes the passengers confuse about the route but the Great Circle Route is the shortest route between the two locations