For domestic flights in 2026, the standard recommendation is to arrive at the airport at least 2 hours before departure. This window is designed to account for modern travel variables: roughly 30 minutes for parking or transit, 30-45 minutes for checking bags and navigating security, and 45 minutes for the boarding process (which typically begins 30-40 minutes before the "doors close" time). If you are flying during peak holiday periods, on a Monday morning, or from a major hub like Atlanta (ATL) or London Heathrow (LHR), increasing this to 2.5 or 3 hours is safer. Conversely, if you have TSA PreCheck or CLEAR, are not checking any luggage, and have already checked in via a mobile app, you can often arrive 60 to 75 minutes before departure and still make your flight comfortably. However, it is vital to remember that "departure time" is when the plane pushes back; the "gate closing" time is usually 15 minutes prior, and if you aren't at the gate by then, your seat may be given to a standby passenger. Arriving 2 hours early remains the "safe harbor" for most travelers to avoid the stress of a missed connection.