What type of flight is commonly referred to as a "Red Eye"?

A flight referred to as a "Red Eye" is one that departs late at night and typically arrives at its destination the following morning. This type of flight is often designed to help travelers maximize their time at their destination by allowing them to travel overnight while they sleep, thus minimizing the impact of travel time on their daytime activities. The term "Red Eye" comes from the red-eye effect that passengers may experience due to lack of sleep.

Flights that depart early in the morning, operate with minimal passengers, or are delayed overnight do not fit the definition of a "Red Eye," as they do not involve a schedule that allows overnight travel combined with an early morning arrival.