Business travelers once looked to airline club rooms as calm oases that offer quiet areas to relax, work, conduct important phone calls or, perhaps, catch a nap. These days, it's not unusual for airline-operated and independent lounges to be as crowded and noisy. Congested airport terminals and gates have areas that many frequent travelers are willing to pay a fee to avoid – and there are alternatives on offer. Outside the United States, travelers seeking alone time might check into one of the Napcabs equipped with beds, worktables, touch screens, WiFi and baggage storage, located inside Germany's Munich or Berlin-Tegel Airports. Elsewhere, Yotel offers cozy, cabin-like hotel rooms equipped with creature comforts such as futon-like beds, wifi, and flat screen TVs, located inside airport terminals in Amsterdam, London and Paris. Coming soon: Istanbul and Singapore. Domestically, travelers seeking sleep, a place to work or a quiet place to have a phone conversation have an increasing range of options.

Downtime at Dulles?

A Sleepbox for passengers traveling through Dulles International Airport.

In the near future, Boston-based Sleepbox is expected to cut the ribbon on a post-security micro-hotel on Concourse A at Dulles International Airport. The 16 stand-alone modules have no bathrooms, but are soundproof spaces with mood lighting, Wi-Fi, and beds with memory foam mattresses, among other perks. Bookings are made via a smart phone app that allows guests to unlock their room, and control special features. The average hourly rate for compact rooms (about 30 square feet) is $25 per hour. Standard rooms (45 square feet): $35 per hour. After the first hour, additional 15-minute increments are $5 for the compact room and $7.50 for the standard-room. Rates top out at $120 for a 12-hour stay in a compact, and $140 for 12-hours in a standard.

Room to relax

Minute Suites location Source: Minute Suites

Short-stay hotel chain Minute Suites has six post-security locations in four airports: Two in Atlanta's Hartsfield-Jackson International Airport; two in Dallas-Fort Worth International Airport, one in the Charlotte Douglas International Airport atrium and another at Philadelphia International Airport. The basic 56-square-foot suites have sofa daybeds with a pull-out trundle beds, sound-masking systems, HDTVs (with DirectTV and Netflix) that can also be used as computers and Internet. A few suites in the DFW location are larger. The company is adding four additional locations in Atlanta, a second location in Charlotte, and has just announced plans to set up shop at Baltimore/Washington International Airport (BWI), in addition to other airports. An uptick in the number of millennial travelers is helping drive Minute Suites' expansion. A recent Hipmunk travel survey found that more than half of all millennials (54.4 percent) would like airports to offer nap rooms. "The second most requested amenity was board games," said Minute Suites co-founder and CEO Daniel Solomon. "And we have now added board games and other desired services such as exercise cycles and yoga mats to our locations." Rates for Minutes Suites start at $42 per hour, and drop to $32 per hour after two hours. The overnight rate (8 hours) is a flat $155. Showers (available in DFW Terminal D) and Charlotte Douglas International Airport are $20, with suite rental; $30 without.

Alone in a box

Source: Minute Suites

Jabbrrbox offers travelers private, phone-booth sized quiet places to work and make phone calls. They are available at New York's LaGuardia Airport Terminal B, Pittsburgh International Airport (Concourse B and C) and on Concourse B at Cincinnati-Northern Kentucky International Airport (CVG). Recently, two new booths were installed in New York's John F. Kennedy International Airport Terminal 4. Users make reservations using touchscreens on the exterior of each unit. Once inside, there's Wifi, a desk, a power panel and environmental controls, among other things. Jabbrrbox pricing is $10 for 15 minutes, $15 for 30 minutes, $30 for an hour and $60 for two hours.

Source: Jabbrrbox

Work, stand, stretch

Varidesk at DFW Airport Source: Varidesk