And sometimes the problem isn't about losing a city but gaining one; you may have paid a hefty premium for a non-stop to Europe but out of the blue your airline converts it into a connecting flight. Unfortunately, there's not a lot you can do in a situation like this.
As for the dropped route gotcha, speed is your ally. The quicker you get on the phone with the airline, the more options you'll have. Usually the airline will try to work with you but if all else fails, you should get a full refund so you can get a flight on another carrier. In that case, though, brace yourself for the possibility of paying more especially if you need to make changes close to your original departure date. As I always say, ask the airline what it can do for you in the way of vouchers or other assistance; you won't get a thing if you do not speak up.
5. The free ticket "gotcha"
There are times when you want to redeem your miles with your airline's code share partner airline, only to find your 'free' ticket to Europe costs hundreds of dollars in fuel surcharges and taxes. Now this won't occur with all redemption activity, of course, but when it does - gotcha!
6. The multi-airport "gotcha"
You've just flown into New York's LaGuardia and look around for your next flight but can't seem to find it anywhere. A quick glance at your ticket reveals the gotcha: your next flight takes off from JFK. This happens, especially if you're flying multiple airlines and there's really only one thing you can do: pay close attention whenever you book a flight but especially a flight with one or more connections and see what airports they fly in and out of. Already booked? Check your itinerary carefully. 7. The unruly passenger "gotcha"
I don't know if there's something in the water or it's just the dog days of August but there have been a rash of 'bad passenger' incidents this month, bad enough to delay or divert flights. One particularly notorious case involved a man on a JetBlue flight who allegedly ranted at seatmates before punching a passenger and groping a pregnant woman. The cross-country flight diverted to Denver. Nothing much the average passenger can or should do about such incidents beyond letting the professionals - flight attendants or even air marshals - deal with it. Interference on your part, no matter how well meaning, could result in you too getting tossed from a plane.
Now if you're the 'victim' of a delayed or diverted flight, the airline may offer you a voucher for your convenience but if they don't, go ahead and ask. United recently atoned for a nightmarish delay by providing passengers with free meals and hotel rooms, as well as refunding the entire cost of the tickets and giving each passenger a $1,000 voucher. Those passengers earned the largesse; they'd been stuck in the Shanghai airport for three very long days.
The opinions expressed by Rick Seaney are his alone and not those of ABC News.