Thanksgiving is one of the most popular times of the year for air travel. Unfortunately, if your travel plans take you to or through the East Coast in the next two days, you could be in for some severe weather. Two big storms are expected to bring heavy rain and ice to much of the Eastern Seaboard on Tuesday and Wednesday.

If you're flying, hopefully you will be able to avoid the worst of this week's weather. But if your flights are canceled or delayed, here are a few tips to help you get where you're going with as little hassle as possible.

Time is of the essence
With so many people traveling on Thanksgiving, airplanes tend to be very full. As a result, if your flight is canceled -- or your first leg is delayed and you're sure to miss your connection -- the airline may have a hard time rebooking you before the holiday. There just aren't many unsold seats available to accommodate a large number of passengers.

That's why time is of the essence for rebooking. If you're already at the airport when you learn that your flight is severely delayed or canceled, you should get on the customer service line immediately, but you should also call your airline's customer service or reservations phone number.

It's easy for the airport customer service agents to get overwhelmed by itinerary change requests if several flights get canceled in a short period of time. In many cases, you will get through to an agent on the phone faster. That could be the difference between snagging the last seats on the next flight and having to come up with "Plan B."

Plan ahead
Better yet, try to save yourself the hassle of flying through bad weather by rebooking in advance. Many airlines will allow you to change your itinerary without penalty if you are flying to, from, or through an airport that is expected to experience bad weather. By Monday evening, Delta Air Lines (NYSE:DAL), United Continental (NASDAQ:UAL), and US Airways (NYSE: LCC) had already issued travel advisories for the Northeast and waived change fees for a number of airports. Check with your carrier for full details.

Like many carriers, United Airlines is allowing itinerary changes due to expected severe weather (Photo: United Airlines).

In most cases, when a travel exception is issued, the airline waives its normal change fees as long as you rebook on other flights in a few days. If you can get out before the storm, that might be your best bet. If you are connecting through a major Northeast hub like Newark, Philadelphia, or Washington, it may be possible to rebook on an itinerary that avoids most of the bad weather.

Phone a friend
If you do need to make alternate travel arrangements from the airport, it can be helpful to call a friend or family member who is at home to help you with the process. Sometimes your best option is to fly into or out of an alternative airport, and having a few backup plans can be helpful for when you finally talk to customer service.

However, figuring out your options can be tough when you're peering at flight schedules on your smartphone. Having an "ally" with a computer can be a big help for determining which flights still have seats available and can get you to your destination in time for the holiday. Again, the more information you have when you finally get a customer service representative, the better your chances of getting a good result.

Good luck out there!
Weather-related delays and cancellations are one of the worst parts of air travel. On a holiday week like this one, it can be even worse since airplanes (and airports) are crowded, and everyone is on essentially the same schedule.

Luckily, some advance planning and a good strategy can help you avert the worst of the inevitable delays and snafus over the next few days. As a general rule, the more proactive you are in rebooking once you find out that your original itinerary won't work, the better off you will be. Good luck, and have a safe and happy Thanksgiving!