Most airlines allow passengers to bring only one carry-on bag and one personal item on board, meaning anything else has to be checked in, and often at high expense.

And of course, many airlines are strict on the size and type of the bag you try to pass off as carry-on. So you’re pretty much left with two undesirable options: pack less stuff, or pay to check the rest in.

A couple reckon they’ve designed the perfect solution: two bags of luggage that masquerade as one.

Johnathan Webster and Gizem Mut-Webster are the husband-and-wife team behind Wool & Oak, a company that is becoming famous for its newest launch: a clever two-part duffel bag designed to get around airlines’ strict bag policies.

The bag looks like a single backpack, which you can carry around like any other.

But once you’re on the plane, the bag unzips to create two separate parts: a slimmer backpack and a larger bag. There are a couple of Wool & Oak bags the backpack can be zipped onto, turning them into one.

And with that, boom — you’ve just skipped around the airline’s strict one carry-on policy, and snuck two bags on.

Well, they were technically one bag when you boarded.

“I haven’t been caught yet,” Johnathan Webster told Business Insider.

He said he’s managed to store as much as two weeks’ worth of luggage in the two-in-one duffel bag, and reckons it’s saved him hundreds of dollars in check-in fees.

The couple’s company Wool & Oak, which launched through Kickstarter, makes a whole range of stylish travel bags.

The brand was started after the couple returned from global travels and found they had struggled to find exactly the functional but unfussy bags they needed.

The couple told Business Insider over the past two years, Mr Webster has taken close to 60 flights and avoided having to check in his luggage.

If you’re keen, the Voyager bag set, which is made from Italian leather and TSA approved, is available to pre-order and will set you back about $800.