Fliers faced with a lengthy layover or delay can sometimes feel stuck in airport limbo. Exhausted from hours in transit, travellers without enough time to leave the airport will often pay to access a lounge or hunker down at a restaurant for free wi-fi.But an additional option – on-site sleep pods or suites – is an increasingly popular amenity in airports from Europe to the United States. The concept can be traced to Japanese capsule hotels, first developed around 1980, and appeal to travellers looking to nod off or work in private without having to pay for a traditional hotel room or leave the airport.Minute Suites started operating 13 pods at Philadelphia International Airport in late 2009 and five at the Hartsfield-Jackson Atlanta International Airport in 2011.These bijoux private mini suites are bookable in 15-minute increments, 24/7, for travellers to sleep, relax or work. Each 7ft-by-8ft cabin is equipped with a daybed with bedding and pillows, an alarm clock, TV, desk and chair.According to Daniel Solomon, co-founder and CEO, construction is currently underway for two locations at Dallas/Fort Worth International Airport, one of which is slated to open this month, while the company is also developing a location at Chicago O’Hare International Airport, which will open in 2014.Solomon and his Minute Suites partners all come from healthcare professional backgrounds. “We always viewed our goal as creating a healthier travel experience,” Solomon said. Between factors like restless nights of sleep on board and unhealthy in-transit eating habits, many fliers are fatigued and unhealthy when travelling.Weary travellers have been escaping airport chaos and bunking up in-terminal for some time outside the US. Yotel, which offers “small, smart spaces in which to sleep, relax, refresh and connect,” according to Jo Berrington, Yotel marketing director, opened airport capsule hotels in London’s Gatwick and Heathrow airports in 2007, and in Amsterdam’s Schiphol Airport in 2008, each of which contains 32 or more private cabins. All are bookable by the hour with automated check-in and check-out, and contain a bed, free wi-fi, a workstation, shower and flat screen television. And they are looking to expand.“We are already talking to a number of US airports,” Berrington said. “They all see a huge opportunity to enhance their offering with a concept like Yotel, offering a place to stay for just a few hours in between flights, a long transit or the night before an early flight departure.”A number of similar products and services are available at international airports. Napcabs are German-engineered, 4sqm self-service units, equipped with amenities such as double beds, worktables and air conditioning units.Fliers can purchase time in the pods by the hour – currently only in operation in Munich Airport but set to debut elsewhere internationally – with the swipe of a credit card on the door.Additional brands include SnoozeCube, which has 10 soundproof units equipped with a bed, television, free wi-fi and outlets to charge electronics at Dubai International Airport, and No 1 Traveller, which operates a block of rooms with beds, en-suite bathrooms, TVs and wi-fi at London’s Heathrow, although they only are open from 6 am to 10 pm.