Let’s say that you miss your connection or your flight has been cancelled. Don’t panic. There’s a couple things that you can do.
First of all you need to know your rights. If the flight is delayed/cancelled due to weather or air traffic control (ATC), US airlines do not have to provide accommodations or meals. However, if your flight is delayed/cancelled due to something within the airline’s control such as mechanical, operations, crew staffing the airline is responsible for your well being. In those circumstances, they must put you up in a hotel and provide meals if you have to endure an extensive delay.
As for getting for your destination, my best tip is to be courteous to the customer service agent and DON’T BE A JERK. They’re also doing their best. If you have access to the airline lounges, proceed up there and use the customer service representatives there. The line will be much shorter. If you have access to flight information, start taking a look which flights still have space. If you can tell the representative what routes you want to take and there’s space available, you’ll get out of there much quicker. Don’t only check your the carrier that you’re flying, check other carriers out of the same airport. Most airlines have agreements that allow you to fly on another carrier if the delay/cancellation is non-weather/ATC related. While you’re standing in line, you may also want to call up the airline’s customer service hotline. In some cases, you may be able to get help there quicker than if you wait in line.
In order to avoid getting into this situation, it is best to be proactive. Some airlines like United have the ability to backtrack the plane which you will be taking. By doing this, you can tell with a good probability whether there are any delays. If you notice that you may not make the connection, contact the airline and see if they can back you up on an earlier flight or a later connection. You may need to do this at the airport.
Finally, I’ll cover an edge case here. If you’re traveling and due to non-weather/ATC related issues, you won’t make the event that you’re traveling there for. This is what is refereed to as “trip in vain”. In these circumstances, you need to very clearly explain to the customer service agent the purpose of the trip and that the trip is in vain if you continue travel there. Most airlines I’ve seen will either offer to send you back home and refund the ticket. However, policies vary from airline to airline.