Probably the most frequent cause a voyage is canceled is weather. Occasionally this is pretty obvious, like if you're sitting in the middle of a snow storm, and no one is going anywhere.
Sometimes you look outside, and it's sunny and calm. How can the flight be canceled for weather like that? Think about it. The weather might be occurring somewhere else. Maybe there are awful thunderstorms on the East Coast, and that's the location the flight is arriving from. Maybe the flight is arriving from sunny Florida, but it's coming THOUGH a hub in the center of one of those storms. Maybe there is a sandstorm in the Sahara or a typhoon in Japan. Weather anywhere in the planet can affect your flight if it is an extended haul air travel.
An alternative reason flights may be canceled is mechanical problems. If this is the situation, you want them to cancel, but it's tough not to feel frustrated anyway.
Or else an escape could be canceled for the reason that there have been delays, and at this point the crew has been waiting for too long. There are rules about what time they can take off and when they can't.
If your escape is canceled, the moment you hear that your airplane is not going anywhere, call the airline's toll-free number. (It's a smart plan to have it programmed in your cell phone.) Get into the line at the counter, especially if it's rather tiny, but make that call while you're standing in line. There's a strong odds you'll get rebooked more quickly on the phone than at the counter where a few of overwhelmed airline employees are being swarmed by a plane overflowing with disgruntled fliers.
Ask what your options are. Really, it pays to have an outline of alternatives before you arrive to the airport. Correct, most times you won't need to take advantage of the alternatives, but with canceled flights, the quicker you can act on those alternatives, the more apt you are to go on your way while everybody else is still looking them up.
Nearly all airlines will rebook you, with no fees or penalties, on the next flight on which room exists. Not necessarily on the next flight, but the next trip on which room is on hand. Through holiday periods or really bad weather situations, this may perhaps be more than merely hours. If you seen the news the last few years, you know it can even be days!
If the delay seems too slow, ask the agent if there might be a seat on an alternative airline. Remember they are in competition, but airlines will often endorse your ticket to a different carrier to try and get you on your way in a timely way. You'll have the most stroke of luck if the flight is on a partner airline.
If these things don't work, propose solving your trip obstacle by linking through an alternative city or going to an alternative airport. Remember, all of these suggestions only labor if your canceled flight is pretty much an isolated circumstance. If all the airlines are canceling flights, as they have got to in bad weather... Patience is the only thing that will succeed.