What is the definition of a Red Eye flight?

A Red Eye flight is commonly understood to be a last scheduled flight that departs late in the evening and arrives at its destination the following day, often early in the morning. This terminology is primarily used in the United States and refers specifically to the overnight travel aspect, where passengers tend to be traveling while most are sleeping. The term "Red Eye" originates from the potential for passengers to have red, tired eyes upon arrival due to lack of sleep.

While some may think of a flight that departs late in the evening, the correct definition emphasizes the arrival at the destination the following day, highlighting the overnight journey aspect. This distinction is vital for understanding how Red Eye flights fit into travel schedules and passenger needs, as they enable travelers to maximize their time at the destination by traveling overnight.