[stepstep]

> a great circle is the shortest route between any two places

Wouldn't it be faster to adjust the heading to point directly to the destination and then fly in a straight line?

[Patrick_Devine]

Remember that we live on a sphere (or something approximating one -- it's a sphere that bulges). A great circle route actually is a straight line, it's just that on a 2D map it looks like you're constantly turning.