Both United and American Airlines offer two different types of airport lounges with vastly different amenities and experiences.There are standard run-of-the-mill membership lounges — dubbed the United Club and Admirals Club, respectively — and then there are exclusive spaces, respectively called the Polaris Lounge and Flagship Lounge, which are reserved for business-class passengers.United Polaris Lounge Washington Dulles (Photo by Zach Griff/The Points Guy)In recent years, the two carriers have invested significantly in building out their poshest lounges. American now operates five Flagship Lounges (across its biggest international gateway hubs), while United has six Polaris Lounges (one in every domestic hub, except for Denver).Want more airline-specific news? Sign up for TPG’s free new biweekly Aviation newsletter.These business-class-only lounges offer an upgraded experience compared to the standard membership clubs. This includes more luxurious seating arrangements, including nap pods and a plethora of phone booths, an elevated buffet with better catering, top-shelf liquor, shower suites and more.It’s no surprise then that the airlines limit access to these lounges to their most lucrative flyers. This helps avoid overcrowding in the lounges, while also reserving this experience to those paying the big bucks to sit in the pointy end of the plane on international flights.American Airlines Flagship Lounge JFK (Photo by Zach Griff/The Points Guy)While both airlines allow business-class flyers to use the lounge before long-haul flights, American is more welcoming than United when it comes to a carve-out for certain domestic flights — those seated in American’s Flagship business or first class on premium transcontinental routes receive access to the Flagship Lounge. (American also admits its top-tier elites before long-haul flights, regardless of the cabin flown.)Meanwhile, those flying in the United Polaris lie-flat pods on the same routes are relegated to the standard United Club.In fact, I recently flew from Newark to San Francisco on one of United’s premium transcontinental coast-to-coast services. I booked a business-class ticket, and despite enjoying the Polaris “hard product” on board the plane, I was locked out from using the Polaris Lounge before my flight.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.Instead, I spent a good chunk of a 3-hour departure delay sitting in the much less premium United Club at Newark. The airline currently operates just one “standard” membership club at Newark Terminal C, and it’s dark, outdated and notoriously overcrowded.United Club Newark (Photo taken pre-pandemic by Zach Griff/The Points Guy)(United is building an upgraded club in the C3 concourse. Until then, the airline also operates a temporary pop-up club near Gate C93, but that’s only used during peak departure windows.)During the departure delay, I kept thinking to myself that had I been flying American, I would’ve had access to the Flagship Lounge, where I could relax and enjoy the upgraded amenities included with my business-class ticket.Of course, I understand United’s perspective for keeping the Polaris Lounge limited to its long-haul international passengers. The airline can limit overcrowding and reserve the space for travelers driving the most revenue.United Polaris Lounge Washington Dulles (Photo by Zach Griff/The Points Guy)But, premium transcontinental routes have historically been some of the most profitable in the domestic network. Business and deep-pocketed leisure travelers splurge for the lie-flat pods, which can go for more than $1,000 in each direction. Plus, many corporations award their travel contracts to airlines based on the coast-to-coast product offering and the number of frequencies.In United’s case, the airline recently restarted serving the JFK airport with flights from San Francisco and Los Angeles, after a more than 5-year hiatus.Pulling out of JFK in 2015 has since been deemed a “strategic mistake” by United executives, who say that the airline lost corporate contracts and other big spenders due to the move.United at JFK (Photo by Zach Griff/The Points Guy)It’s apparent that these transcon routes are some of the highest-profile flights in United’s domestic system, yet the airline is letting its business-class flyers down by denying them entry to the Polaris Lounge before travel.If the airline wanted to upgrade the pre-departure experience, it could consider letting these passengers into the fancy lounges. And, if United is worried about “cheapening” or overcrowding the experience, it could even limit access to those paying for business fares, and exclude those redeeming miles or upgrades from using the Polaris Lounge.This is a move that’s been recently popularized by United’s Star Alliance partner north of the border. Air Canada’s top lounge, the Signature Suite, is only accessible to those paying for business-class fares — others can use the standard Maple Leaf Lounge before departure.Air Canada Signature Suite (Photo by Zach Griff/The Points Guy)Another alternative is to restrict transcon business-class passengers from using the Polaris Lounge bistro area. Each Polaris lounge has a restaurant-style dining room (in addition to an extensive buffet) with waiter service and cooked-to-order menu items.United could differentiate the transcon and long-haul premium travel experience by only allowing those traveling internationally to use the dining room — which would still represent a big improvement compared to the status quo for coast-to-coast travel.It’ll ultimately be interesting to see if United ever adjusts its Polaris Lounge access policy to include premium transcontinental routes. Until then, American Airlines will continue to take the cake when it comes to offering the best domestic ground experience that your money (or miles) can get you.