To those of you who have read all of the chapters of Airline Fare School you have my thanks and congratulations.

I hope you get the chance to put some of the things you've learned into practice when you plan a future trip.

At the very least, try to be creative when you structure trips. Use the tinker toys approach, and avoid being a slave to the tyranny of "round-trips" when something else might work better.

I'll continue to write the occasional post about something interesting, unusual, or downright wacky when it comes to airline fares but this is the end of the structured approach of Airline Fare School.

To make it easier to get access to the series, here's a table of contents:

AIRLINE FARE SCHOOL

Introduction:  Welcome to Airline Fare School

Chapter 1:     The Basics, part 1
Chapter 2:     The Basics, part 2
Chapter 3:     The Basics, part 3
Chapter 4:     One ways and round trips
Chapter 5:     Connections, Stopovers, Through fares, Point-to-Point fares
Chapter 6:     Open jaws and Tinkertoys
Chapter 7:     Circle trips
Chapter 8:     Secret stopovers, Part 1
Chapter 9:     Secret stopovers, Part 2
Chapter 10:   Secret stopovers, Part 3
Chapter 11:   Differences between domestic and international fares
Chapter 12:   How you can research airline fares
Chapter 13:   Class dismissed!

In an online travel world that is heavy into blogging, emailing, Facebooking, and tweeting the latest bargain fare between Points A and B, there is little out there that gives knowledgeable consumers access to the raw data - the airline fare and rules displays that underlie it all. For those who have slogged through AFS and garnered a better understanding of how airline fares work, you certainly qualify as more knowledgeable, but where do you go from here to apply what you're learned?

There are two channels that I am aware of, which allow an ordinary consumer to see fare and rules displays. One is free, and the other has a modest monthly charge. (If you know of others please comment back with the link.)

The primary purpose of Airline Fare School is to acquaint you with the rules and structure of airline fares mostly as the system functions within the U.S. Nonetheless I've brought in references to international travel in the early chapter on understanding connections and stopovers, as well as more recently in the second and third installments of secret stopovers.

In this chapter I'll cover some things worth knowing about international fares even if you may never really put them to use.

At root the purpose of fares for international air travel is no different than for domestic travel; they serve to get the passenger from Point A to Point B. However certain features of fares - in particular higher priced full-fare economy, business and first class tickets - have different attributes that don't exist for U.S. domestic travel.

This is the last installment of Secret Stopovers .

US Airways - San Francisco to Paris (free stopover in Philadelphia)

US Airways allows a stopover in Philadelphia (PHL) or Charlotte (CLT) on pretty much any fare I've looked at between the U.S. and Europe. PHL is both a domestic hub for US Airways as well as its primary hub for service between the U.S. and Europe. Currently served European cities from PHL include Dublin, London, Madrid, Paris, Frankfurt, Munich, Amsterdam, plus Tel Aviv in the Middle East. From CLT the airline operates nonstop to London, Paris, and Frankfurt.

Fares to PHL tend to be on the high side so if a business trip (or leisure trip) comes up on short notice you might be able to add Europe on. You may actually save money over just buying a round-trip ticket to Philly, or at least be able to fly to Europe for not too much more.

We're going to go two directions here: Hawaii and the Caribbean.

But first let's consider why stopover provisions even exist in the first place.

At one time and even now, it's not always possible to fly between two places with nonstop flights or nice, neat connections. In order to use one airline from Point A to Point C via Point B. an overnight stop may be necessary. The airline knows that if its fare is broken point-to-point, it is likely to be more expensive than a competitor's. In such an instance the airline is trying to turn a negative into a positive, or at least into a neutral.

This is the part of Airline Fare School I've been most looking forward to writing.

Why?

Because the information I'm going to present is both obscure and invaluable to the right traveler. And in the galaxy of websites that inform you daily, hourly, by the minute, on the ups and downs of airline fares, I've never read anything about what I'm going to write in this and subsequent chapters.

What you're going to learn underscores what I've said from the start of AFS: knowing the rules and ins-and-outs of airline fares can enable you to plan better trips.

I'm not sure how many "Secret Stopovers" chapters there will be, but you can count on least two.

This is a circle trip:

- Sacramento to Atlanta (stopover, not connection)
- Atlanta to Cleveland (stopover)
- Cleveland back to Sacramento

And if you're thinking this is a triangle, not a circle, I completely agree but the industry term is circle trip so we'll stick with that.

This lesson builds on what you've learned before, especially in the preceding chapter about open jaws.

If you haven't already read that, then I strongly recommend you do so - "AFS # 6 - Open-jaws and Tinkertoys" - and then come back here. On the other hand, if you've already read AFS # 6, please step right this way.

I'll get to the Tinkertoys part in a while. Let's start with open-jaws.

World's best cat, Catdog, poses in the shot below illustrating the concept of the open-jaw.

CELEBRITY SPOKESCAT CATDOG BRINGS TO LIFE THE "OPEN-JAW"

I trust that all of you have flown at one time from Point A to Point C, changing planes in Point B. (Example: Seattle to Fort Lauderdale on Continental changing planes in Houston.) That, of course, is known as a connection or a connecting flight.

It could also involve two (or more) different carrers, such as Delta from Salt Lake City to Seattle and Alaska Airlines from there to Anchorage.

With the growth of the hub system since airline deregulation in the late 70s, connections have increased as carriers built certain of their airports into huge operations with banks of flights coming and going all day.

Think Dallas/Fort Worth for American, Chicago for both American and United, Denver and San Francisco for United, Philadelphia and Charlotte for U.S. Airways, and so on. Southwest is sometimes cited in error as an airline that doesn't operate connecting hubs but this is not true: Chicago-Midway, Phoenix, Las Vegas, and Baltimore all serve as hubs for Southwest.

In Airline Fare School # 1, 2 and 3, we covered four basic elements including fare displays, rules, routings, and booking the flight in the appropriate inventory for the fare you want.

Here in AFS # 4 you're going to get acquainted with what a published one-way fare is and what a published round-trip fare is. By the way, round-trip fares, can also be called excursion fares but we'll stick with the term "round-trip".

Right away you're thinking, "Oh, come on. I know the difference." Well, you might be surprised about that and it's important to understand the clear distinction before we move on to some other concepts.

Let's take a look at a fare display for American Airlines between Sacramento (SMF) and Cincinnati (CVG) for departure on 9 November.