United Airlines has just announced its latest scheme to charge its customers for a service that used to be given for free. For an annual subscription of $249 those who fly with the airline will be exempt from any charges when booking up to two bags onto a flight. In 2008 United was the first airline in America to start charging customers $25 to check in a second piece of luggage. The new scheme also allows up to eight people on the same booking to be exempt the additional baggage charges so is likely to be attractive to families as well as semi-frequent fliers.

Analysts say that the idea will help United to boost revenue and also encourage customer loyalty. Those who sign up for the annual deal will feel obliged to take advantage of it every time they travel and therefore choose to fly on United even if other carriers are offering cheaper ticket prices.

In the second quarter of 2009 charges for additional luggage on airlines earned the business $669.6 million in revenue according to the U.S. Transportation Department. This is around three times as much as was earned in the second quarter last year.