Image copyright Getty Images Image caption The average person only burns an extra 6p worth of calories from flying every year
There are doubts about whether a system which allows people to buy an extra 5kg of baggage for free would ever really be adopted by many.
The system is called Allow More – and it was dreamed up by hi-tech air conditioning company Osipow.
Its research says, on average, people could save as much as £31,000 by buying that extra 5kg.
But there are still few airlines to actually test it out.
Take a short flight from London to Glasgow
Passengers flying from London to Glasgow use a joint BMI/BA service. Passengers change planes at Cardiff and fly on to the Republic of Ireland, or fly on to Dublin.
Passengers flying from London to Glasgow use a joint BMI/BA service. Passengers change planes at Cardiff and fly on to the Republic of Ireland, or fly on to Dublin. The overweight charge for the passenger carrying the heaviest bag is £100 – or, the equivalent of 5kg, each way.
The overweight charge for the passenger carrying the heaviest bag is £100 – or, the equivalent of 5kg, each way. The allowance is fixed, unless the passenger purchases the extra 5kg
Under Osipow’s optional scheme, a passenger could start buying the extra 5kg when they take their flight.
For example, instead of the original cost of £100, the passenger would pay £36.60. But, if they decided they wanted to carry on flying, they would pay an extra £2.80 each way.
The system would be relatively easy to set up, as the weight allowances are fixed.
The complicated process would, of course, need a third party to collect the weight and feed it to the airlines and airports, who would then charge the passenger.
However, little has been done to test the system yet.
In addition, the easiest of all the systems – getting a pass for a free 6kg or 7kg baggage allowance – has been largely turned down.
At British Airways there is no policy whatsoever on providing free baggage allowance, but passengers can claim refunds for checked baggage with a local partner airline that offers discounted flights.
The US Federal Aviation Administration has opened its routes for testing. But the agencies involved in the so-called Federal Skyway Park Project say they have yet to conclude which airlines would make the best candidates.
They say that the pilot programme should last no more than a year, but it will take several times longer to complete the final analysis.
The first of those conclusions are due to be published by the FAA in December, giving the aircraft manufacturers time to develop the correct technology.