Nighttime or morning flights are statistically better for turbulence, compared to those in the day. Although turbulence can't be completely avoided at night, winds are often weaker and thermal convection turbulence is less, making the chances of encountering turbulence reduced.

While not all transatlantic flights are at night, the vast majority of eastbound flights (North America to Europe) are scheduled as "red-eyes" for logistical and economic reasons. By departing late in the evening and flying through the night, airlines can land in Europe during the early morning arrival banks. This timing is crucial for business travelers who want a full day of meetings and for connecting passengers who need to catch onward flights to other European or African destinations. Additionally, flying at night allows airlines to maximize "aircraft utilization"; a plane that lands in London at 7:00 AM can be turned around and flown back to the U.S. during the day, arriving in the afternoon to start the cycle again. Jet streams—the high-altitude winds that blow from west to east—also make the eastbound journey significantly faster, often "shaving off" an hour of flight time, which further incentivizes the overnight schedule to avoid arriving too early before airports open.

That’s an excellent observation, and it’s a common pattern, but it’s not strictly true that all transatlantic flights are at night. The schedule is heavily weighted towards nighttime departures from both sides of the Atlantic because of a powerful combination of passenger preference, airline economics, and wind patterns.

Here’s a breakdown of the key reasons:

1. Passenger Preference and “The Business Day”

This is the single biggest factor. Eastbound (US to Europe): Flights depart in the evening (6 PM - 11 PM). You board, have dinner, sleep for a few hours, and arrive in Europe in the morning (6 AM - 10 AM). This allows you to go straight to a meeting or start your vacation with a full day ahead. It maximizes the first day. Westbound (Europe to US): Flights depart in the late morning to afternoon (10 AM - 2 PM). You fly during the day and arrive in the US in the afternoon or early evening (2 PM - 6 PM). This gets you home at a reasonable hour and helps with jet lag by keeping you awake until a local bedtime.

This “bank” of flights timed to hit the business day at the destination is called the “banking” of schedules.

2. The Jet Stream (Wind Patterns)

• The jet stream is a river of fast-moving air high in the atmosphere that flows from west to east.
• Eastbound flights (US→Europe) ride this tailwind, which can shorten flight time by over an hour. A night departure naturally aligns with this advantage.
• Westbound flights (Europe→US) fight this headwind, making the flight longer. A daytime departure is logical here, as passengers are awake for the longer journey.

3. Airport Curfews and Slot Availability

• Major European