Yes, planes can and frequently do depart at 1:00 AM, though this depends heavily on the specific airport's noise curfews and regulations. Many major international hubs, such as those in the Middle East (Dubai, Doha) and parts of Asia (Singapore, Hong Kong), operate 24/7 and have "banks" of flights departing in the middle of the night to align with global time zones. However, many European and Australian airports—such as London Heathrow, Sydney, and Frankfurt—enforce strict night curfews (typically between 11:00 PM and 6:00 AM) to minimize noise pollution for local residents. Departures at 1:00 AM from these "curfewed" airports are usually only permitted in exceptional circumstances or for specific "quiet" aircraft types under a strict quota. For travelers, a 1:00 AM departure means you effectively arrive at the airport on the evening of the previous day, so careful attention to the date on the ticket is vital to avoid missing the flight.