THE AIRLINE industry has announced new guidelines recommending smaller carry-on bags to free up space in planes’ overhead bins

Global airlines announced Tuesday the new guideline. It is not binding and means that many existing bags currently in compliance with airline rules would not be given preferential treatment in the boarding process.

While details of how the guideline will be implemented are murky, and could vary from airline to airline, it raises the possibility that many fliers would be forced to check their favourite carry-on bag.

Fliers might ultimately need to buy smaller suitcases or pay a fee to check their bags, typically around $25 each way.

The recommendation by the International Air Transport Association suggests an “optimal” carry-on size at 21.5 inches (55cm) tall by 13.5 inches (34cm) wide by 7.5 inches (19cm) deep. That’s smaller than the current maximum size allowed by many airlines.

For instance, American Airlines, Delta Air Lines and United Airlines all currently allow bags up to 22 inches (56cm) by 14 inches (35.5cm) by nine inches (23cm) – although gate agents don’t always enforce those more-generous measurements.

“Once again, the airlines find a way to make their problem the passenger’s problem – and an expensive problem at that,” said travel industry consultant Henry Harteveldt.

The lack of overhead space is due to airlines cramming too many seats on planes and charging passengers to check their suitcases, he said.

The airline trade group says the new guideline will not necessarily replace each airline’s rules on bag size, but gives them a uniform measurement that “will help iron out inconsistencies”.