BALTIMORE (WJZ)–When you board an airplane, loading your carry-on bag can be a struggle. Different planes accommodate different size luggage.

Amy Yensi has more on the new push for a one standard.

Just because you hope you’re carry on will fit, doesn’t mean it will.

For some struggling to load luggage in the overhead bin is a better choice than paying to check it in or waiting for a suitcase after landing.

“You can there and get in, get out when you’re off the plane. You don’t have to wait for your bags to come out,” said Tim O’Branski.

The International Air Transport Association–a trade group representing 250 airlines worldwide issued a new best-size guideline for carry-ons.

The new guideline for a carry-on is 21.5 inches tall, 13 1/2 wide and 7.5 inches deep.

But, it’s smaller than any currently allowed by U.S. carriers. Chris Goater is an IATA spokesman. He says European airliners are already getting on board because they realize the lack of a standard- size is a problem.

“You can just have certainty that your bag is going to get on and even fit under the seat in front of you,” said Goater.

Ben Mutzabaugh writes an aviation blog for USA Today, and says though it’s not required, airlines in the U.S. could soon adopt the one-size fits all approach.

“If you start seeing global airline after global airline adopt this, there will be more pressure for a standard that could hit the us airlines,” Mutzabaugh says.

Cheryl Hardy’s says having a standard-size would save all travelers time and trouble.

“Quite often you can’t fit your carry on into the overhead spaces. I think it’s a great idea,” she says.

For now it’s just an idea. The guideline is not mandatory and carriers are free to ignore the recommendation or adjust it.

8 international airliners have signed on as supporters of the new guideline, none are u-s airliners.