With most airlines charging for checked luggage, consider shipping it ahead. To send a 25-pound bag from Chicago to Orlando, for example, can take several days but costs less than $20 via parcel post, FedEx or UPS ground services — versus the $25 charged by most airlines. Currently, Southwest doesn't charge for the first two checked bags weighing less than 50 pounds, and JetBlue allows one free checked piece.

Depending on your airline, you might save even more by shipping bags weighing 50-plus pounds. Delta, for example, charges $90 for that "overweight" bag on domestic flights, whereas shipping it coast to coast would cost less than $66.

Also, says AirfareWatchdog CEO George Hobica, "you'll enjoy better shipping tracking than the airlines can offer, plus better security. And you can breeze through the airport without waiting in line to check in your bags."

Sid Kirchheimer writes about consumer and health issues.