Smaller carry-on luggage could be coming to an airplane near you

Think a carry-on is a carry-on the world around? There is no official, standardized carry-on bag size for all airlines—nore than 50 different allowable sizes have been identified by the industry. And even within a single airline, the allowed size of on-board luggage can differ from one aircraft to the next.

A worldwide standard would assure passengers of the right carry-on fit for all airlines, and that's what the International Air Transport Association (IATA) wants with its Cabin OK proposal. This industry group that represents 260 airlines worldwide, has proposed a one-size-fits all carry-on size. Unfortunately, the proposed size is probably smaller than the carry-on you use now.

At 21.5 inches high x 7.5 inches deep x 13.5 inches wide, the proposed IATA size is 21 percent smaller than the maximum allowable dimesions on American, Delta, and United (22 inches high x 9 inches deep x 14 inches wide) and 43 percent smaller than the allowance for JetBlue and Southwest (24 inches high x 10 inches deep x 16 inches wide). The new size is intended to fit both in the overhead bin and underneath the seat on a Boeing 737 and Airbus A319/320, narrowing the difference between your carry-on bag and your underseat personal item. 

See an update on the status of Cabin OK below.

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IATA spokesman Chris Goater says that the proposed Cabin OK size is not a maximum, but rather an "optimum" size that will create the best odds of ensuring that your bag goes on board with you. He says that each airline can and will maintain its own maximum limit but, as is the case currently, the maximum size does not guarantee that the bag will get on board. "Airlines that have agreed to recognize the Cabin OK logo know that it is OK not to stick it in a sizer or put it in the hold."

For some passengers who travel on multileg flights with different airlines, Cabin OK might be easier than deciphering IATA's Most Significant Carrier rule, which defines which airline's baggage allowances and charges apply on a one-fare, multiairline journey.

But even with Cabin OK, it doesn't seem that passengers will be absolutely, positively assured that their bag won't be sent to the cargo hold. IATA qualifies its guidelines by saying that "those bags with a Cabin OK logo will have a priority (determined individually by each airline) for staying in the cabin should its cabin capacity be exceeded and some baggage need to be moved to the hold."

Under the IATA proposal, participating luggage manufacturers would affix the IATA Cabin OK logo (shown above) on conforming carry-ons to allow gate agents to quickly identify size-compliant bags. The high-end American luggage-maker Tumi has already signed on to the program, as have two Japanese brands, Lojel and Sunco, and the Dot Drops brand made by French company Jump, according to John Vermilye, CEO of Travel Sentry and Okoban, the standard-setting companies that are coordinating the participation of luggage manufacturers.

But some luggage companies are distancing themselves from the proposal. Samsonite International, the world's largest luggage company, issued a statement saying that it is not collaborating with the IATA at this point "as none of the U.S. airlines have stated that they are in agreement with this new initiative yet." The company also said that it will offer "appropriately sized carry-on products" to fit any changes that major U.S. airlines adopt. German luggage maker Rimowa said, "we want to make it quite clear that we do not support plans to reduce the standard size of carry-on luggage, and neither have we provided such a recommendation to IATA or any airline company."

As for the airlines, Tom Windmuller, IATA's senior vice president for airport, passenger, cargo, and security, said that 30 to 40 airlines are "interested" in Cabin OK. Nine have already accepted the proposal, including Avianca, Cathay Pacific, Emirates, Lufthansa, and Qatar. He adds, "We are confident that over the next several months we will get a number of major airlines on board." (Watch a recent IATA interview on the new carry-on size and Cabin OK below.)

A one-size-fits-all carry-on would indeed ease the pain for travelers—except for the part about buying new luggage to be assured of the right fit—and for airlines, but it's unclear whether Cabin OK will become widespread. The IATA guidelines are voluntary, even for the organization's member airlines, and the group says that the plan will be implemented only with sign-on from a a certain number of airlines, or airlines representing a certain percentage of passenger volume. 

The new optimal-size bags with the IATA Cabin OK logo are expected to be available later this year.

—Susan Feinstein