The high level of airfares is always fair game as a topic of conversation when frequent travellers get together. It is an even more popular topic for politicians, who appear to believe, probably erroneously, that cheap fares are a good vote-catcher. Some fares are certainly high, but it is still possible to fly to most parts of the world for considerably less than the full standard fare, given the assistance of a professional travel agent. The key word when it comes to the difference between high fares and low fares is 'flexibility'. If you are prepared to be flexible as to the day or time of year when you want to travel and let the airline slot you onto a flight that it knows is likely to have empty seats, you can nearly always find a cheap fare. But this may well mean you have to buy your ticket either several weeks in advance or at the very last minute. Frequently your stay at the destination must include at least one Saturday night - a frequently criticised requirement that is imposed by airlines to minimise the risk of business travellers trading down from the normal full fare to the cheap rate (on the theory that few business people want to spend a Saturday night away from home). And with most cheap fares, once you have booked your flight, you can usually switch to an alternative service only on payment of a fairly hefty cancellation or amendment penalty.

The other side of the flexibility coin is that if you want complete freedom to change or cancel your flight without penalty, you have to pay for the privilege, which means, in practice, the expensive full fare.

Economics

The economics of the wide gap that exists between the highest fare and the lowest is not quite so crazy as might appear at first sight. If business travellers want the flexibility to change or cancel their reservations at short notice, seats will often be empty because the airline has been unable to resell them, and the cost of flying that seat still has to be paid for. The price of a fully flexible ticket also has to take account of the 'no show' factor - those passengers who have a confirmed reservation but do not turn up at the airport and fail to notify the airline that they want to cancel their flight. So there is an implicit bargain between the airline and the passenger when it comes to a cheap fare. The airline offers a discount in return for a commitment from the passenger (underpinned by a financial penalty) that he or she will actually use that seat.

Flexibility

Many business travellers can probably be more flexible about their air travel schedules and can still save quite a lot of money, provided they don't mind travelling at the back of the aircraft with the masses. For example, if you are planning to attend a conference, the date of which is known a long time in advance, you can frequently buy an APEX fare at anything up to half the cost of the full fare. But always bear in mind those heavy financial penalties if you suddenly decide to cancel or change your flight.

Business travellers will also find that it is often worth looking around for a package trip, such as those offered by specialist tour operators to tie in with a trade fair. Some travel agencies and tour operators also offer attractive packages to business destinations that provide not only the airfare but also hotel accommodation for a total price that is often less than the normal business class fare. Needless to say, this type of package does not offer the flexibility of the full-fare ticket and you will probably not be able to change your flight if your business schedule overruns.

If you are planning an extensive tour within a region such as North America, the Far East or Australia, it is well worth investigating the many airpasses available, for instance those issued by US and Canadian domestic airlines, which offer multi-coupon or unlimited travel over their networks for a given period (although there are usually some restrictions on routing). For travel to the USA, there are also some remarkably good-value deals on fly-drive trips, with car hire being charged at only nominal rates in many cases.

Some of the best deals for business travellers are to be found in the round-the-world fares offered by a number of airlines, which can enable you to plan a complicated itinerary at a knockdown rate.

Frequent flyer programmes

In the competitive world of aviation, where the frequent traveller is king - or queen -'loyalty programmes', as the 'frequent flyer' programmes are classified, have become the norm. Passengers collect points or benefits each time they fly with a particular carrier and they redeem them for a free ticket for a partner or for some other benefit. There was a time that fear of the various tax authorities' view on such schemes prevented most airlines outside the US from offering frequent flyer programmes. If they were to offer a scheme it was heavily disguised and travellers had to have a US address. Competition has forced a more open approach and nearly all airlines have their own scheme today or link in to that of another carrier, and the hotel chains are also now following suit.

There are specialist magazines - such as Executive Travel or Business Traveller magazine in the UK- aimed at frequent travellers that list all the latest offers on airfares, deals and frequent flyer programmes.

Bucket shops

The best-known source of discounted air tickets is the so-called 'bucket shop', a phrase that was first coined at a travel industry conference in the early 1970s to denote an outlet specialising in the sale of air tickets at an 'illegal' discount. Such is the power of the media that the term - which was derived from shady activities in the nineteenth-century US stock market - is now universally understood. The term consolidator is now more frequently used within the industry and has gained legitimacy as a result of lighter regulatory control.

Back in the early 1970s, the world of bucket shops was a pretty sleazy one, based on back rooms in Chinese supermarkets or in flyblown first-floor offices in Soho. One or two of the early entrepreneurs actually ended up in prison and some of the cheap tickets that found their way into the market place had, in fact, been stolen. One bucket shop, which traded as a 'reunion club', ended up owing more than £620,000 to thousands of people who had been saving up to visit relatives abroad, not to mention another £614,000 that was owed to airlines. The owner of this club was eventually jailed for trading with intent to defraud. He knew that the 'club' could not meet its liabilities and yet he continued to trade for almost a year.

Failures still do occur occasionally, but the aura of back-street sleaze has virtually disappeared. Outlets are being opened in the high streets of provincial cities by respected companies with long experience of the travel business, and most of the household names in retail travel are now able to supply discounted tickets. At one time the Association of British Travel Agents (ABTA) officially banned its members from offering 'illegally' discounted airfares, but dropped this rule when the restrictive practices legislation began to bite on the travel business. Nowadays many bucket shops are members of ABTA, and all discounted scheduled airfares are now covered by the Civil Aviation Authority's consumer-protection machinery. This makes it less likely that the consumer will be left out of pocket if a bucket shop goes bust as repayment will be due from a bond.

The CAA recently tightened its protection rules further, requiring all consolidators to be covered by bonds unless they hand over tickets to their clients on the spot, immediately after receiving payment. The agent must print details of bonding and an Air Travel Organiser's Licence (ATOL) number on its documents. Consumers can check the validity of the ATOL by calling the CAA.

It is worth taking a closer look at the discounting phenomenon and at what makes it 'illegal', if indeed it is. It is an economic fact of life that, on average, the world's scheduled airlines fill only two- thirds of their seats, so there is a very powerful inducement to fill the remaining one-third by any means possible. Assuming that overheads have been covered by the two-thirds paying 'normal' fares (although this is not necessarily a valid assumption), anything earned from one extra passenger means a bigger profit or a smaller loss - provided that the airline can earn some valuable hard currency.

The 'illegality' of discounting stems from the internationally agreed convention that governments can approve airlines using their airspace, and most countries have provision in their legislation that makes the sale of tickets illegal at other than the officially approved rates. In the UK, the legal position is not quite so clear cut. British airlines are regulated by the CAA and there is specific legislation that lays down heavy penalties against discounting. Foreign airlines are separately controlled by the Department of Transport and, depending on whether there is a specific provision on tariffs in their permits, they may or not be liable to be brought before the courts for discounting.

There is a third class of airline - the so-called 'offline carrier'- which does not actually operate services into the UK but maintains sales offices here. These airlines can, quite legally, do whatever they want in terms of discounting, because there is no law that can catch them.

All this is somewhat academic because no British government has ever tried to enforce the law, which suggests that perhaps it is time for it to be repealed. The CAA, too, has rarely refused to sanction a new low fare filed by an airline (although it could intervene if it felt the fare was 'predatory'- in other words, designed to put a competitor out of business). However, the authority has frequently refused applications by airlines to increase their full-price fares.

The passenger's viewpoint

The risk of losing money at a bucket shop has been reduced drastically by tighter consumer protection rules. Even the danger than an agency could go under, leaving you scrambling for an alternative deal, should not be exaggerated.

Only a tiny proportion of bucket shop clients suffer financial loss in any year, and there are plenty of satisfied customers who have managed to make substantial savings on their trip. Perhaps word-of-mouth recommendation from a friend is a good way to find a reliable outlet for a discount fare and in recent years the strengthening of consumer protection legislation means that any outlet displaying the ABTA and ATOL symbols is a pretty safe bet.

It is a good sign if a bucket shop has been established for some time in good premises with a street-level office. If possible, you should make a personal visit to assess the knowledge of the staff rather than just relying on a telephone call. Ask as many questions as possible and find out any likely snags such as a protracted stopover en route in an unattractive part of the world; and make sure you know which airline you're flying with.

It is a good indication of a bucket shop's reliability if it holds an Access or Visa appointment, because the card firms check the financial integrity of their appointed outlets thoroughly. Use of a credit card also gives you added security because, under the Consumer Credit Act, the card company becomes liable for provision of the service you have bought in the event of the retailer's failure. It is also a good sign if the office is a member of the Association of British Travel Agents (look for an ABTA sticker) or licensed by IATA (the International Air Transport Association) because you are then protected by the association's financial safeguards.