> When will the airlines learn about straight lines being the shortest distance? We are leaving on vacation and will be zigzaging all over the country.

Simple matter of cost and resources and something called exponential levels of growth.

Let's say you're an airline operating out of three different airports. You want to offer non-stop flights between all your different airports. How many routes do you fly (not counting return trips)? Just three! Airport A to B, B to C, and A to C.

Now let's add just one airport. How many routes do you have to fly to get non-stop flights between all the airports you service? The number jumps up to six. AB, BC, CD, AC, BD, and AD.

Add one more airport, for a total of five, and you're now flying 10 routes. Make it six airports, and you're flying 15 routes. Make it seven airports, and you're flying 21 routes.

Service 40 airports, and suddenly you're up to 780 routes. Service 80, and you need to fly 3160 routes.

For major airlines that service this many airports and more, offering non-stop service between any two of those airports is essentially impossible. Airlines operate close enough to the margin as it is. This is why airlines tend to have hubs -- airports that serve as stop-over spots for a large number of flights. It allows an airline servicing 80 airports to offer one-stop flights between any two airports by operating just 79 flights, rather than the 3160 flights that would be required for all non-stop service.

So, yeah, a straight line, non-stop flight between two locations would surely be the most economical way to fly *that* route, but it's cheaper still not to offer a non-stop flight on that route at all.