A cocktail served at the new United Airlines Polaris lounge at Newark Liberty airport. Leslie Josephs | CNBC

There are more ways than ever to gain access to an airport lounge, away from the masses: frequent-flyer status, credit card perks, day passes, subscription services. Those won't get you through the door at United Airlines' new 27,000-square-foot Polaris lounge, which opened on Monday at Newark Liberty International Airport. The Polaris lounge is reserved for travelers with tickets aboard Polaris, United's new international business class, and international first- and business-class passengers booked on its Star Alliance partners. Booked in first class on a domestic ticket or short-haul business class? You're off to the more basic United Club lounges.

Hors d'oeuvres served at the new United Airlines Polaris lounge at Newark Liberty Airport. Leslie Josephs | CNBC

The airline is raising the velvet rope for the bright new facility, which features showers with rainfall shower heads, 10 daybeds with Saks Fifth Avenue-branded blankets (the airline said the blankets are washed on site) and an extensive menu that includes dishes such as polenta fries and braised lamb.

Shower facilities at the new United Airlines Polaris lounge at Newark International. Leslie Josephs | CNBC

United's business-class ticket prices vary but a round-trip from Newark to London's Heathrow Airport in early July was about $4,200. The airline, like its competitors, is trying to court well-heeled travelers, but the Polaris rollout, which includes new seating and lounge construction, has been slow since it was first announced in 2016. The airline needed more space for the lounges because the product appeared more popular than it anticipated, leading to construction delays, spokesman Robert Einhorn said. The airline set up a website where the public can track its progress on installing the new Polaris seats on board and when it opens lounges. Both United and Delta are in the middle of rolling out new seating in premium international cabins. United's Polaris has pods instead of seats, while Delta is offering suites with sliding doors. United last month said it would offer some business-class travelers access to a private terminal and a lift in a BMW 7-Series sedan. Just about 5 percent of travelers in the first seven months of 2017 flew in a premium-class cabin, which includes business class, but they accounted for around a quarter of revenues, according to the International Air Transport Association, a trade group representing the world's biggest airlines.