Imagine that you are about to take off on a relaxing vacation abroad or an important business trip. Everything has already been planned and organized, your ticket has been paid for and issued and your suitcases are packed.

You arrive ready, willing and able at your airline's check-in counter, and suddenly, the ground stewardess informs you that she is sorry, but all the seats are taken and you cannot board the flight.

This may sound like a story, but unfortunately, it is a very realistic scenario as a result of a phenomenon called "overbooking."

This happens when airlines book a larger number of passengers than there are seats on the plane in an attempt to minimize financial loss.

A.H., a businessman and frequent flyer on El Al, discovered this the hard way: Along with 50 other people, he was unable to board an El Al flight from New York on Passover eve due to overbooking.

This occurred despite the fact that he was carrying a ticket and arrived at the airport three hours before takeoff, as instructed.

Although he was offered compensation ($400 or a free ticket in return for not suing in the future), A.H. refused the offer and was put on an alternate flight run by Air France.

But he did not make it on time to his family seder.

A.H. submitted a complaint to the Israel Consumer Council. El Al responded that it actually overbooks less than do other airlines, and does so only in cases where passengers might cancel for various reasons without prior notice to the airline.

So that you will not find yourself in this irritating situation, TheMarker has prepared the complete guide to overbooking:

Many companies openly overbook. However, there is no set percentage or number of overbooked tickets per flight. Among other factors, computerized systems take into consideration factors such as the season, school vacations, commercial fairs, cultural events and also the route, as some are more prone to cancelations than others. For example, past experience teaches that flights from Israel to Germany have fewer passengers who fail to show up than do flights to Spain. In some countries, such as Sweden, the percentage of no-shows is so low that the number of overbooked tickets is also very low.

The season also has a significant effect on overbooking. In the summer, for example, the percentage of overbooked seats will be much higher than in the winter, and can range from 2 to 10 percent of the total number of passengers on the flight. According to Robbie Hershkowitz, the CEO of Brussels Airlines in Israel, the reason for that is the Israeli traveler's behavior: "A family that wants to secure its summer trip abroad simultaneously books flights on several different airlines and doesn't always bother canceling the irrelevant reservations, so they continue to appear in the system."

Holiday eves are another time when passengers are likely to fall victim to the overbooking plague, as the businessman's complaint demonstrates. At these times, the enormous demand causes travel agents to pressure airline companies to pack as many people as possible on the plane, even if it is already full. And despite sophisticated statistical forecasting systems, airlines cannot always successfully predict when overbooking will fail and force passengers to remain on the ground. This is due to unforeseen occurrences such as changes in the type of the plane and the total weight it can carry, bad weather, transportation problems and strikes.

The bad news is that nobody is obliged to notify you if you buy a ticket on an overbooked flight. The good news is that there is a way to lower the risk of staying on the ground. Hershkowitz explains how it works: "The first passengers to arrive at the check-in counter get on the plane. Passengers who have tickets but arrive last run the risk of not being let on the flight, because it is already full. There is no requirement that airlines inform passengers ahead of time that a flight is overbooked or to what extent." In other words, arriving at the airport three hours before takeoff is highly recommended.

There is more good news, though in this case, for the rich only: According to Hershkowitz, the overbooking problem usually occurs in coach section; it very rarely happens with seats reserved in business or first class. One of the reasons for this is the simple fact that airlines have a much harder time finding alternative flights for these passengers.

The companies claim to make an effort to solve overbooking crises by finding volunteers among the passengers waiting for the flight. Patrick Amar, director of Air France and KLM airlines in Israel, explains how this works: If an overbooking problem arises, airline representatives seek passengers in line who will volunteer ahead of time not to board the flight in return for financial compensation and an alternative arrangement. For instance, the compensation fee for a flight from Ben-Gurion Airport to Paris is $300 per passenger, while for a long flight to New York, the fee climbs to $500. Amar tells of passengers who intentionally arrive at the airport at the last minute in order to receive the financial compensation and board another flight, and this way gain an additional night at a Tel Aviv hotel.

If you failed to get on a flight due to overbooking, notes the Consumer Council's legal advisor, attorney Zeev Friedman, the airline is required to fly you to your destination no more than four hours after the originally scheduled takeoff for a short flight, or six hours for a long flight. If you receive an alternative flight within this time frame, you will not receive additional compensation. However, says Friedman, if the scheduled time for the alternative flight exceeds these limits, you are entitled to receive, in addition to the flight, at least $50 to $200, as well as reimbursement for additional reasonable expenses due to the delay, such as phone and lodging, upon presenting receipts. Friedman adds that the regulations also cover cases in which the passenger was offered an alternative seat on the same plane: If moved from a more expensive seat, he is eligible to receive the cost difference; if moved to a more expensive section, he will not be charged an additional fee.

If you accept your deserved compensation from the airline, you will be required to sign a document stating that you will not make any future claims against the company. "The law gives the passenger the choice between receiving compensation or turning it down and suing for damages in court," clarifies Friedman.

However, industry veterans say that not all the companies adhere to these rules, and in any case, the client can always go to court. But, explains attorney Einat Bracha, the legal advisor of the Public Trust Organization, signing this waiver can harm the consumer's case, since, upon arriving in court, he will have to prove that he was unlawfully coerced into signing the form. Therefore, Public Trust views this conditioning of compensation that the customer legally deserves on a forfeiture of rights or future claims as unacceptable.