Question 1: “Has anyone tried flying from Aisa to the U.S. on a straight line path?”

YES! Every day. Remember that a great circle path is the ONLY straight line between two points on the planet.

Forget about paper maps. There are several different types (projections) and they all provide a distorted view of the earth. Take a look at the globe illustrations above. The “curved” line only looks curved when you looking at it from an angle. When you look at the route from directly above, the line is straight. When flying this line in an aircraft, the nose of the jet (assuming no wind) points straight down the line, pointing at the destination. The aircraft never turns. As you pointed out, the compass and our heading move significantly as we scoot across the globe, but the aircraft remains flying the straight line. The reason for heading changes is that we are using magnetic or true north as our heading reference point. If it were possible to move magnetic north to Hong Kong and use Hong Kong as our “North” reference, we would maintain the same heading all the way Hong Kong.

You can prove this for yourself using a globe and a piece of string as I did in the article. Play with it a bit. Stretch the string in a straight line between New York and Hong Kong (or anywhere else). Looking directly above it, it should appear straight. //

Stephen Kosciesza says:
FEBRUARY 3, 2017 AT 9:54 AM
A comment, if I may, rather than a question. It’s sort of a corollary to all that you’ve said, and it looks at the picture sort of the other way round. I’ve looked at some of the questions asked; I’m not sure if this will confuse or clarify.

If you start flying exactly north or south anywhere in the world, and you keep flying straight, you’ll continue to fly north or south (at least until you get to the North or South Pole).
If you start ON THE EQUATOR, and fly exactly east or west, and you keep flying straight, you’ll continue to fly east or west.

Begin flying in any other direction–or begin flying east or west, somewhere away from the Equator–and you will have to turn gradually if you want to keep the same geographical heading (I deliberately avoid calling it the same “direction”).

So as a broad example, if you’re in the northern hemisphere and you set out flying east (or, for that matter, northeast or southeast), you have to keep bearing left in order to maintain east (or northeast or southeast).

I think a good way to picture this, in your mind or on a globe (NOT a paper map!) is to consider a trip going always east at a high latitude–i.e., one of the circles very near the North Pole. It’s easy, then, to see that from the plane’s point of view, it’s flying in a circle going left.

As another exercise, imagine that you are 50 feet from the North Pole. You face east, and start walking–always east. You’ll have to walk in a circle roughly 300 feet (more exactly, 314.15926… feet) around, constantly turning left. If you do not, you will walk east for ONE INSTANT, and then you’ll be going more and more south of east. Walk/swim the same way for long enough, and you will pass a point 50 feet from the South Pole–walking east for one instant before heading more more north.