(The author is a Reuters contributor. The opinions expressed are his own.)
June 13 (Reuters) - Jamming as much as possible into carry-on luggage has become routine for travelers, considering the fees many airlines charge for checking baggage. But those bags may be barred from overhead bins this summer.
Some travelers are discovering that bags that once were acceptable are now too big and must be checked.
The airlines say it is about space. Industry experts argue that the carry-on crackdown is a ploy to get more revenue.
"Airlines have for years turned a blind eye to their own baggage restrictions," says Tim Winship, editor of FrequentFlier.com, a travel website.
Among the three largest airlines - American Airlines , Delta Air Lines and United Airlines - only United says it is taking a harder line on the size of luggage destined for overhead bins.
Earlier this year, the airline let travelers know it was going to enforce size limits, disqualifying any bag that exceeded the following measurements: 22 inches in height, 14 inches in width, and 9 inches in depth.
"Customers with the right size bags were telling us that often times there was no more room on the aircraft for their carry-on bags," United spokesman Charles Hobart said. "This is a response to customer feedback."
One problem for travelers is that a lot of bags sold as acceptable carry-ons are 15 inches wide, in violation of the three largest airlines' policies. They are, however, still permitted on the largest of their rival carriers.
While the other airlines say they have not gotten tougher, they acknowledge that during busy times they are more aggressive about policing carry-on bag size. During vacation periods, for example, they pay more attention to what passengers are trying to bring on board, Delta spokesman Morgan Durrant said.
Airlines have tried to keep up with increased demand to bring bags on board by getting larger bins on new planes. "All those bins get bigger and bigger; yet it's never enough," said Robert Mann, an airline analyst for R.W. Mann & Company Inc and a former airline executive.
Airlines are trying to catch oversized bags as early as possible, because it is easiest to charge passengers for checking a bag at the counter, Mann said. If the bag has made it all the way to the gate, time pressure often prevents airline workers from even trying to collect a fee.
The three largest airlines share the same carry-on size limits, which happen to be smaller than what is permitted on rival carriers. Southwest Airlines, JetBlue Airways and Spirit Airlines all allow bigger carry-ons. But Spirit, which is known for low-base fares and a raft of fees, charges as much as $100 for carry-ons.
When choosing a carry-on bag, consider avoiding one with wheels, says Tim Leffel, editor of PracticalTravelGear.com. Wheels gobble up room because they count in the measurement.
Travelers should also avoid over-stuffing their carry-ons, he says. "Nothing should be put into an outside pocket of a 9-inch-wide carry-on except flat things like magazines and papers," Leffel says. Otherwise, the extra bulge will exceed regulations.
These are the maximum carry-on bag sizes permitted on America's largest airlines:
* American: 22 inches x 14 inches x 9 inches
* Delta: 22 inches x 14 inches x 9 inches
* United: 22 inches x 14 inches x 9 inches
* Southwest: 24 inches x 16 inches x 10 inches
* JetBlue: 24 inches x 16 inches x 10 inches
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