Let’s be honest: A crowded airport lounge without a seat in sight is usually less appealing than an empty gate area. Business travelers are looking to optimize time and minimize stress—and they’re willing to pay for it. The “lounge-within-a-lounge” concept is taking off at airports across the US, providing business travelers with reservable, private spaces ideal for high-level meetings. ILLUSTRATION: Alex GreenDifferentiated SpacesIn the US, newer lounges that require an international business-class ticket for access, like the network of Delta One Lounges or United Polaris Lounges, are delivering on that promise. Delta, for instance, offers an á la carte, bistro-like dining experience, soundproof phone booths, and even external monitors for focused work at each of its flagship business lounges.