Don't forget that you will need to taxes and other fees when you collect that free flight.

Berlin - Most airlines entice passengers into using their frequent-flyer programmes. But not every traveller manages to take multiple flights a year to rack up enough air-miles to benefit.

The airlines generally let passengers keep miles for a few years before they expire, so even the infrequent flyer may luck out and get a free flight at some stage.

“It's free to join, so you're not losing anything,” says Ravindra Bhagwanani, CEO of Global Flight, which advises airlines on their frequent flyer programmes. “For most people who don't fly frequently, getting one free flight out of it is an exciting reward.”

But don't forget that you will need to taxes and other fees when you collect that free flight. They are not included in the bonus.


How many flights do you need to reap the rewards of a frequent-flyer scheme?

If you take long-haul flights two or three times a year, you could get a free flight within a few years, says Oliver Kuehn, editor-in-chief of a German flight magazine.

As long as you pick the right scheme, that is.

“If you are getting the best deal, you would pick up around 22 000 miles off a return economy flight from New Zealand to Europe,” says Kuehn.

With British Airways' Executive Club, that would be enough to claim two free return flights between Britain and Germany - a popular connection for international tourists - costing around 8 000 miles each.

But not all airlines are willing to dish out benefits at such a cheap rate of exchange.

Lufthansa charges 30 000 miles for any free return flight within Europe - an unattainable threshold for infrequent flyers.


How do I choose the right frequent flyer scheme?

The devil is in the details.

Star Alliance, an airline consortium that includes Lufthansa, offers no benefit to those who only fly every now and then, says Bhagwanani. Their rewards are too expensive - and on top of that, the passengers have to pay all fees.

Kuehn's advice is not to necessarily use the air-miles membership card of the airline you travel with most often.

“Sometimes you can get more benefit by exploiting an airline alliance instead.”

For example: “If you fly a lot with Lufthansa, you can actually get more for your money by crediting the Lufthansa miles flown to the United Airlines frequent-flyer programme. Since United credits you with more miles, you attain a free flight more quickly.”


How much difference is there between airlines and airline groups?

The general rule is, that if you pay less up front for a flight, you are likely to get fewer air-miles in credit. Some airlines will credit you with 100 percent of your miles, even for the cheapest ticket categories. The strict ones will only credit you 25 percent, says Kuehn.

The most generous big airlines are British Airways (OneWorld) and United Airlines (Star Alliance).

“The stingiest airline programmes are Lufthansa's Miles and More, and Flying Blue at Air France, which only credit you 25 percent of miles you fly if you're sitting in the cheapest seats.


What should I bear in mind when I'm booking flights?

Firstly, you need to look at the cash price, says Bhagwanani.

“And make sure you grab all the miles you can.”

If you don't fly often, you should never pay any extra just to acquire air-miles. “It's rarely worthwhile.”


Can I only use miles from flights to obtain credit?

There are a few other options. Some store cards and credit card schemes will let you credit points to an air-miles account.

“If you have a credit card issued by one of the airlines, you can also get extra miles,” says Kuehn. This means the amount you spend will be converted into air miles using a formula.

Lufthansa alone offers credit-card customers more than 300 different ways to collect points. But it's important to consider the fees you will incur: “You need to spend around 10 000 euros on your credit card every year to make the fees worthwhile,” says Bhagwanani.