I'm a total loss with this one!

I'm a total loss with this one! HELP

You are the science advisor for an organization that has been tasked with planning the flight path for a new experimental airplane that operates off of solar power. The president of the organization reveals his plan to fly over various cities that lie due south of your location at 65oN. The target cities lie at 40oN, 20oN, 0o, 30oS, and 60oS. The president's plan involves flying at a constant speed after takeoff from your location and flying along a straight southerly trajectory. In your post, after reviewing the president's plan for the experimental plane, what flight path would you recommend he take to have the smoothest flight? Be sure to explain your recommendation with examples and much detail.