Thankfully, I've not experienced a cancellation - goodness willing, I won't. However, the way things are these days I thought I'd ask our expert Fodorites here:
What are the steps one must take when a flight is cancelled? I fly alone, am an older woman and although I realize I can ask while there, there's nothing like the expertise on this board. Any tips on how to make it less stressful? Thank you very, very much.

Curse. You might also have a list of airline reservation numbers appropriate for your trip. If you get cancelled, run to a phone and try calling rather than waiting in line. This tactic worked for me once. I was flying from Charlotte to Columbus, Ohio, when I found out from the monitor TV screen in the airport that my flight had been cancelled. I was with a very savvy traveler who said get to a phone.
I did, and booked the next flight.
Then the Ramada Inn pulled a stunt on me that I still remember. I was supposed to meet my wife's mother and my "second" mother in Columbus at our motel: the Airport Ramada. We both had guaranteed reservations and we had given our credit card numbers in both cases.
Ramada cancelled our reservations and did not know where the two people we were to meet had gone. Moreover, the people at the Ramada could not even give us a good list of hotels in the area of the airport so we could start making calls to try to locate them! We finally located them through a third party!! They did not know where we were, exactly, and we did know where they were!

I guess I am a semi-expert because I have just experienced two cancellations. The one in May was truly a learning experience. I was super impressed by the savvy business people who went to their laptops to find any alternate means of air / train transportation. Also wish I had a video of the 7 or 8 block sprint some of them made to the refund / compensation desk. I was just coming out of a rest room and saw the whole thing from a side view. Some people literally ran over other people. By the way, our wait in that line lasted another 2 full hours after the 20 plus hour "delays" we had just experienced. In that 20 hours I had gotten to know some of my fellow passengers. That is my advice to a woman traveling alone at the present time. In my case, I had started a card game and gotten a little "Canterbury Tales" thing going with a few because we had already seen so much crying etc. that it needed a certain edge of humor or whatever. We had a 13 member family going to a wedding in Chicago that they had missed- and the people literally had LOST IT, in front of most of us. From this we had bonded enough to seek some help together. I don't think you should try to trek it alone in the middle of the night anywhere. If it is a reasonable hour that may be different. But if you have some kind-hearted people around you, you can see what different plans that they have devised and made your own accordingly- as ever situation may have become totally different by the time you have realized it. If I am in my home airport, I will just return home now. If I am not and NEED to be somewhere (other than loss of money) for valid reasons- then I will bite the bullet and take lodging (if available), book again and do the horrendous waits. I can not see how screaming at agents will do any good. Our last cancellation turned out to be a great party as we all drove home to Chicago together. (OLDEST was 60 and youngest was 25.) Can't believe how much fun we made out of it, especially since it took us about 3 hours just to reach a place willing to rent us a car on a moment's notice. Yes,we were compensated a free flight. Do you think we want to fly them again? Bob who posted above is absolutely right as those with cell phones were on them even before the final CANCELLED went up on the boards.
But in this case it did not help because by then all AMERICAN and UNITED had already cancelled all theirs for the next day, ahead of time. THOSE flights were cancelled because of weather in other parts of the country and planes would never be back in time
for them. Our plane was supposed to go out 2 days before any storm hit anywhere and it was not considered a weather related cancellation.

I, too, have unfortunate experience with this. I have found through observations that you will get treated MUCH better from the ticket agents if you are not beligerent and mean. I was standing behind a man in Denver, CO (after 10 hours in the airport) who was screaming at the agent. After he was taken care of, I was very polite and sympathetic to the agent and got placed on the next flight with First class. This has happened twice.

I think it is important to remember when this happens that, although they are easy targets, the ticket agents did not have much (if anything) to do with your cancellation.

And no, I do not work for the airlines!

Just some suggestions from personal experience.

My "experience" is based on observing frequent fliers I know and hearing their war stories. The consensus seems to be bring a cell-phone and numbers for major carriers. At the very first sign of trouble, get on the phone to your airline and make a reservation on the next flight out.

What I can't figure out is this: if you hold a ticket on a delayed or cancelled flight, and if you make a reservation on a later flight, does that automatically cancel your existing reservation?

My own experience is that my husband (who travels a lot) takes action as soon as he has any clue at all that the flight is delayed. He'll just re-route us over the phone straight away, and he doesn't wait for the gate agents to make an announcement. He says he has trusted them way too many times and has had 30 minute delays turn into cancellations or huge delays. It appears that he is more likely to do this when the problem is repair-related or when the in-bound plane needed for our flight is not even in the air yet. He's saved us the scene Jeanette describes countless times.

Eleanor,
Well, I'm not "seasoned" in this, but I did have to deal with a cancelled flight. (I think it happens at least once if you fly often!)

Me and my roommate were heading home from San Fran when the plane we were supposed to take had mechanical problems. This was in the days before everyone has a cell phone, and we were sitting by a window. I kept getting more and more suspicious as they kept delaying boarding, and told my roommate to "be prepared". When the announcement came, we were 2 steps away from the agents, and managed to make it 3rd in line. There was only 2 flights going to our general area - one to our airport, the other quite a ways away - to which the airlines stated they would shuttle us. Our third option was to spend the night at a local hotel and take the first flight out in the am. The airlines was willing to put us up at the hotel and give us a voucher for a free flight. Since the next day was Monday, and we both had to be at work, I stated we HAD to reach our airport. I was polite, but firm, and managed to make the next flight. Funny thing was: when we got to our destination, all of the luggage had already arrived earlier - still can't figure that one out!

Plus, when I got to work the next day and tried to impress my boss with my willingness to do anything to get to work (;>), she promptly informed me that if I was ever in that type of situation again, to take up the airline on free flight, hotel, whatever!

The best advice is to remain CALM, don't get angry at the airline agents or other passengers, and enjoy the show. (Most people are at their most comical at times such as these) Just take it easy and be patient.

Michele's calmness advice should be taken to heart, but don't think being calm or "nice" is going to get you a much right now. The days of offering rooms, shuttling you etc. I believe are coming to an end. NO one was given any of those things in my cases AND those who were savvy and got to phones etc. quickly still never got flights out as I met some of them in New Jersey three hours later. You do have to make an adventure of it and try to enjoy the possibilities. By the way, I never did get to work or meeting for TWO days.

When one's flight has been cancelled. Does one have to pay for any other flight they catch from another airline? or do they honor the ticket you have, IF it's another airline? If it's the same airlines, monetarily, what does one have to pay?

MY SUGGESTION/ANOTHER IDEA: I am not (NOT!!) a travel agent, but it has been very helpful to me in the past when dealing with flight delay/cancellation to take advantage of my travel agent's emergency/after-hours telephone hot line (if yours has one) - they can check all available flights at a glance for any airline on their computer and can re-book you in a heartbeat, much faster than the traveler calling around to different airlines themselves. Let them get you on another flight and then approach the ticket agent for hotel/food/$$$ compensation for your delay.