Last Minute travel includes:

If you have to take an unexpected trip because of a family illness or death, almost all U.S. airlines will waive restrictions on excursions fares when you tell them your reason for traveling. You will need documentation from a doctor, hospital, or mortician (usually acceptable after your return) in order to convince the airline of your emergency. Additionally, some airlines (Continental, Northwest, USAir) offer special "bereavement" fares, which are cheaper than regular fares.

In addition, there are several charities and airline employee groups that will arrange (and pay for) what is known as "compassionate" air transportation. These are for passengers and their families who need and can't afford to travel to special medical facilities available in only a few cities. AirLifeLine is a national non-profit charitable organization of over 1,000 private pilots who fly ambulatory patients who cannot afford the cost of travel to medical facilities for diagnosis and treatment. This air transportation service is totally free of charge for patients who qualify. You can visit their web site at AirLifeLine or call them (800) 877-AIRLIFE.
Bump coupons on some airlines permit last-minute travel to most routes the airline flies in the United States. A few carriers permit such coupons to be bought and sold. You can buy them directly from another traveler (the one who was bumped originally) or through a coupon broker. They generally only allow reservations between 24 and 48 hours in advance. If you are flexible, another way to obtain inexpensive tickets is by joining a last-minute travel club. There are several clubs that specialize in last-minute cruise travel, packages, and escorted tours. A few offer air-only charters. Some clubs charge yearly dues (between $30 and $50) and some are free. They notify members of upcoming bargains as they become available through periodic newsletters, post card mailings, or toll-free numbers giving recorded messages on current trips. Despite their name, last-minute travel clubs have knowledge of and access to seats on commercial and tour flights several weeks ahead of departure dates, so you actually don't have to wait until the last minute.
Last-Minute Travel Clubs
INTERWORLD TRAVEL, Miami, Florida, 888-323 0181
GO TRAVEL, Orange, California, 800-695 0600
SAVE ON TRAVEL, Houston, Texas, 800-695 0600

You can also buy last-minute travel from some travel agencies that obtain these bargains by negotiating individual deals with travel wholesalers who have more packages than they can sell. The advantage to buying through a travel agency is the savings on the annual club fee. However, you won't receive regular updates and news bulletins from a retail travel agent who only books last-minute travel as a sideline.