Yes, you can generally leave the airport during a connection, but it depends on your nationality, the transit country's visa laws, and your available time. For domestic connections (e.g., flying from New York to LA via Chicago), you can walk out of the terminal freely, provided you have your boarding pass to re-clear security. However, for international connections, you must officially enter the country, which usually requires passing through immigration and having a valid visa or Electronic Travel Authorization (like an ETA for the UK or ESTA for the US). Experts in 2026 recommend at least 6 hours for a domestic layover and 8+ hours for an international one to account for deplaning, immigration, travel to the city, and the return security check. If your layover is short, the risk of missing your flight is high, so it is often safer to stay in the "airside" transit lounge.