Beyond the prices and restrictions, these differences occasionally matter. On most big airlines, tra

Editor's Note: This story was originally published on July 14, 2011. To see the most recent SmarterTravel articles on related topics, please click on any of the following links: airfare , Ed Perkins , Ed Perkins on Travel , taxes and fees .
You buy a ticket, pay all those pesky extra fees, and take your flight. When it all works smoothly, you pretty much get what you pay for and what you expect. But when you encounter anything out of the ordinary, you may run up against problems you never imagined you would have. And you also discover that the typical hotel reservations airline contract is extremely one-sided: The airline holds you to strict rules and requirements, but it allows itself a laundry list of loopholes hotel reservations and wiggle room. Here are two examples, drawn from recent reports.
All tickets are not created equal. Even within the same class of service and for access to the same seats and cabin service, you find all sorts of different kinds of tickets. The simplest variations are the various ticket classes related to how much you pay, how many restrictions hotel reservations you face, and how easily you can get a refund. A typical airline might have 20 different fare codes in economy.
Beyond the prices and restrictions, these differences occasionally matter. On most big airlines, travelers on the more expensive tickets get priority status for standby seats, upgrades, premium seats, and such. Travelers on the very highest prices so called "full fare" tickets may be exempt from some baggage and other fees. Many foreign lines give only partial frequent flyer credit or even no credit to travelers on the least expensive tickets.
A much bigger difference, however, can often trick you. Most airline contractual commitments hotel reservations are limited to tickets at "published" fares even the lowest "discount" fares (a misnomer, by the way) are actually airlines' list prices for restricted tickets. Real discount fares are the "unpublished" fares at which airlines sell tickets through consolidators and large agencies that arrange "special" or "net" fares. Typically, when you buy one of those tickets, you get only whatever benefits and protections are spelled out in the airline's contract with the consolidator a contract you probably never see. That's why some consolidator tickets hotel reservations are totally nonrefundable, do not earn any frequent flyer credit, can't be assigned to a different airline, can't be upgraded, and don't qualify for any assistance in the event of a delay. Travel consumer activist Chris Elliott recently reported about a traveler who was denied the use of an airline's "unassisted minor" service because the minor's ticket was at an unpublished fare.
Where this can hurt you is when an agency sells you a ticket at an unpublished fare without telling you of any unexpected limitations that fare might entail. Your defense is either to ask the agency for full ticket details or avoid unpublished fares or any fares described as "special."
"Schedules subject to change." You see that a lot; what you don't see is the full version of the contractual hotel reservations commitment: "Schedules subject to arbitrary change by us, the airlines, but not by you, the passengers." Airlines change schedules for a lot of reasons, many justified, at least in business hotel reservations terms. And when an airline changes the schedules for an itinerary you've already paid for, it usually automatically rebooks you. It's also supposed to let you know about the change, get your permission, and offer a full refund if you don't like the change. But that doesn't always happen.
On a recent Asian trip, my friend Don's airline changed his schedule without notifying him or asking if the substitute schedule was OK. As a matter of fact, the new schedule wasn't OK with Don. And being a cantankerous sort, he checked on alternate possibilities and called his airline to ask for a different new schedule. As it happened, the preferred new schedule involved one of his original line's partner lines, and Don had to push a little to get the switch made.
Unexpected schedule changes often arise, especially when you buy a ticket months in advance. To protect yourself against unhappy surprises, do what Don did: Even after a firm booking, recheck your reservation, if your new schedule is unacceptable, look up a better alternative, and present that alternative to your original line.