Airports are no place to sleep, as any weary traveler who has tried to grab a few minutes shuteye during a layover can attest.

But that may be changing, thanks to a new breed of short-stay, pay-by-the-hour micro-hotels popping up in airport terminals around the world.

Based loosely on the concept of the Japanese "capsule hotel," these cabins and boxes allow sleepy travelers to seal themselves off from the surrounding commotion for a 30-minute power nap or a solid night's sleep without having to leave the terminal for a hotel. Some even contain toilets and showers.

In recent years, versions of the concept have emerged from London to Moscow and from Philadelphia to Dubai, with other destinations likely to follow this year.