Here are several tips to keep in mind when you book your flights.

Pad your connections

Pad your connection time, especially when there very few flights you can take if you miss yours.

In the U.S., airlines are operating fewer flights and filling these flights with more passengers. This means more flight delays, as it takes a fuller airplane additional time to board and deplane. Airports have also become more congested and spread out.

Yet, in many cases, the minimum connecting times allowed between flights have not changed for years. If you're booking flights with connecting times of 30 - 40 minutes or so at airports like Chicago O'Hare, you're drastically increasing the chances that you will miss your connection. And even if you barely make it, your checked luggage may not make that flight.

This may not matter much if you're flying into Chicago and connecting into New York's LaGuardia Airport early in the day, as there usually are lots of other flights available through the day if your incoming flight is late.

But, it matters a lot if you're connecting into Billings, Montana late in the day at Salt Lake City, when there are no more flights to Billings that day if you miss your connection.

And, it matters even more if you're connecting to an overseas point, where you may find only one flight available on that route each day. Your missed flight may bag you a 24-hour wait, or a trip via a far-less-direct routing.

Common airline rules for connections

For flights within the U.S., most airlines allow you to take any available connection within four hours. In many cases, you don't have to book the shortest connecting time to get the lowest fare.

For international destinations, you may be allowed to book any available connection within 24 hours, depending on the airline. This means that if you're flying from Dallas to Cape Town, you don't have to reserve an uncomfortably short 45-minute connection, instead of a much safer two- or three-hour one.

Using Priceline and Hotwire tickets

When you use Hotwire and Priceline, you don't usually get to choose your connecting times for the cheapest fares.

Nevertheless, if you find that your connecting times seem too short, some airlines, such as United, will allow you to stand by for earlier flights on the same day when using tickets from Priceline or Hotwire. There's no guarantee that you will get on an earlier flight, but you'll still have your original confirmed reservation if you don't.

On your departure day, call or check online for an earlier flight on the same airline that has seats available to your connecting airport. You can also check to see if there are nonstop flights on the same airline available to your final destination that leave earlier than your reserved departure time. For tips I've given for flying standby, see the link in the bio box of this article.

Avoid changing airlines

Expedia.com especially tends to display budget prices that involve traveling three or even four different airlines on the same day. These low rates are actually a collection of cheap individual fares, which can be very tempting to book.

However, in most cases, you significantly increase your chances of problems each time you connect to a different airline, making limited savings just not worth it. Here are some aggravations you could encounter:

The airlines may operate from different buildings that are not close together.

They may refuse to transfer checked luggage.

But, most importantly, they may claim NO responsibility whatsoever if you miss your connection to the other airline. This can become a very serious problem because budget fares tend to be non-refundable with heavy penalties for changes, or with no changes allowed at all.

For example, if you miss your connection from United to Southwest, which never allow each other's flights on the same ticket, Southwest Airlines will charge you the full difference between your advance purchase fare and the much higher same-day ticketing fare for that leg of your trip. You can't stand by. (United is kinder - if you miss your connection from Southwest to United, you'll be allowed to stand by for a United flight on that same day at no extra fare, in most cases. Still, standby is not as good as a confirmed seat.)

Using more than one airline (with more than one ticket) for the same trip may be tempting when traveling overseas, because of the potential savings. But, be very careful when setting up these trips. In the bio box at the bottom of this article, see the link on how to save using separate tickets.

In summary, pad your layovers and keep your trips as simple as possible, and they will usually be trouble free.

Good luck for a smooth and pleasant trip!