A red-eye flight is any flight departing late at night and arriving early the next morning. The term red-eye, common in North America, derives from the fatigue symptom of having red eyes, which can be caused or aggravated by late-night travel.
Most flights from North America to Europe depart in the afternoon or evening, and arrive the next morning. The reverse journey, however, is usually in the daytime.
- Japan Airlines used to operate red-eye flights from Hong Kong to Tokyo's Haneda, but they have changed to daytime flights. However Cathay Pacific operates one each to Tokyo Narita and Osaka, All Nippon Airways operates red-eye flights from Hong Kong to Tokyo's Haneda twice a week.
- All Nippon Airways operates a red-eye flight from New Delhi to Tokyo's Narita, leaving IGI Airport at 1:25 A.M.
- Asiana, Korean Air as well as Cathay Pacific operate red-eye flights from Hong Kong to Seoul as well as Busan by Asiana and Dragonair.
- Cathay Pacific also operates many such flights. These include red-eye flights both to and from cities in Australia and New Zealand. Cathay Pacific flights that are red-eye only in the Hong Kong-bound direction include those from Bangkok, Singapore and most North American destinations (except Chicago). Cathay Pacific flights that are red-eye only from Hong Kong include those to Seoul, Dubai, Moscow and all current European destinations. The Vancouver to New York (JFK) tag flight operated by Cathay Pacific is also a red-eye service.
- Flights that leave India and South west Asia around midnight arrive in Bangkok, Hong Kong, Kuala Lumpur and Singapore early morning.
- Philippine Airlines also operates red-eye flights from Korea and Japan back to Manila, which also have regular late-night flights from Manila to Singapore.
- Many flights from South East Asia to Japan and Korea depart in the evenings or around midnight, and land at the destinations in the early morning.
- Many flights from East and South East Asia to Europe depart in the late evening or shortly after midnight and arrive early the next morning. Many flights going the other way would depart Europe late in the evening and arrive in the afternoon the next day.
- Indonesian airlines operates overnight red-eye flights from Jakarta to the easternmost province of Papua. With a flight time of 4 to 5 hours and 2-hour time difference, most red-eye flights depart shortly before midnight and arrive around 6 am. Garuda Indonesia also operates daily overnight flights to Beijing, leaving Jakarta at midnight and arriving at around 6 A.M.
- AirAsia X also operates such flights from Shanghai to Kuala Lumpur.
- Pakistan International Airlines flies it's red-eye flights to Lahore, Pakistan from Jeddah, Saudi Arabia.
- Singapore Airlines, Malaysia Airlines, Thai Airways International, and Cathay Pacific operate most of their flights from India to their respective hubs departing the Indian origin between 10:00PM-2:00AM and arriving in their respective hubs between 5:00AM-9:00AM the next morning. For Singapore Airlines and Malaysia Airlines, even the once-a-day flights from Shahjalal International Airport, Dhaka, Bangladesh, Bandaranaike International Airport, Colombo, Sri Lanka, and Ibrahim Nasir International Airport, Male, Maldives to Changi Airport, Singapore depart the origins between 11:00PM-2:00AM, and arrive in Singapore between 6:00AM-8:00AM. For Thai Airways International, their flights from Pakistan (Benazir Bhutto International Airport, Islamabad, Jinnah International Airport, Karachi, and Allama Iqbal International Airport, Lahore) are also red-eye flights leaving their Pakistani origin between 11:00PM-12:00AM and arriving at Suvarnabhumi International Airport, Bangkok, Thailand between 6:00AM-7:00AM the next morning. Malaysia Airlines also operates a daily flight from Tribhuvan International Airport, Kathmandu, Nepal to Kuala Lumpur International Airport, Malaysia, which departs Kathmandu at around 11:30PM and arrives at Kuala Lumpur at around 6:30AM the next morning. For Cathay Pacific, some of it's flights between Hong Kong International Airport and South Asia make a stop in Bangkok. Now, most of the flights have suspended that stop in Bangkok and all Cathay Pacific flights between Hong Kong and India fly directly, while the return flights were red-eye flights. Cathay Pacific used to operate a flight from Hong Kong to Karachi and back, with a stopover in Bangkok, but the operation to Karachi has been suspended due to some problems in Pakistan. The return flight from Karachi to Bangkok was an overnight flight. Now, the only Cathay Pacific destination in South Asia that makes a stop in Bangkok is to Colombo, Sri Lanka, with the return flight from Colombo to Bangkok being an overnight flight. The nonstop flight of Cathay Pacific from Colombo to Hong Kong is also a red-eye flight.
The majority of transcontinental flights are operated during the day, but as of 2010 red-eye flights operate from Perth to Sydney, Brisbane, Cairns, Canberra and Melbourne, and from Darwin to Sydney, Brisbane and Melbourne. Red-eye flights have previously operated from Australia to New Zealand and Fiji. Red-eye flights to Australia operate from various locations in South-East Asia and North America.
TAM Airlines, Azul Brazilian Airlines and Gol Transportes Aéreos offer red-eye flights, called Big Owl (Portuguese: Corujão) flights in Brazil, with over 50 different routes throughout Brazil, all departing between 10pm and 6am. Usually these flights originate in Campinas, Rio de Janeiro and São Paulo bound for Manaus, Belém, Porto Velho, Northeast Brazil, North America and Europe. 
A few overnight flights from Europe to the Middle East and to Russia were being operated in 2009, all of which had a flight time of 3–6 hours and departed in mid-evening, arriving around dawn the next day. In 2012, multiple travel agencies offered budget night flights from the Canary Islands to the mainland of Europe, also generally having a 3-6 hour flight time.
- Middle East
Royal Jordanian airlines operate red-eye flights to and from Queen Alia International Airport to Bangkok, Hong Kong, and Kuala Lumpur. Emirates & Air Arabia has some red-eye flights (U.A.E to India).
Russian airlines operate similarly to U.S. airlines by connecting Moscow to Yakutsk, Irkutsk, and Vladivostock. They last 5–8 hours but due to the northerly latitude the flights can cross as many as 8 time zones during this interval, drastically enlarging the time difference. The flights depart Moscow around 6 pm and arrive at the eastern cities around 6 am the next day. One of the current examples of red-eye flight is Aeroflot's SU783 from Moscow to Magadan, departing 23:05 Moscow time and arriving 14:00 Vladivostok Time on next day (Flight time is 8 hours).
- United States and Canada
Red-eye flights connect West Coast cities to Central and East Coast cities. These typically depart the West Coast between 10 pm and 1 am, have a flight time of 3–6 hours but lose 2–4.5 hours due to the time difference, and arrive between 5 am and 7 am. Red-eye flights also connect Hawaii and Alaska with West Coast mainland cities. Furthermore, red-eyes also connect Honolulu with Tokyo, as the flights only depart at night, and arrive around 6 to 7 hours later.
In the 1930s and 1940s, red-eye flights were not possible, as most airports did not have the equipment necessary to work at night. There are still airports that do not function after certain hours, or have curfews for noise reasons, limiting the number of airports from which red-eye flights can depart.
- Harper, Douglas. "Red-eye". Online Etymology Dictionary. Retrieved 31 July 2013.
- Gol pede autorização permanente para operar vôo noturno Folha Online. Retrieved on April 07, 2009.
- TAM lança ofertas corujão a partir de R$ 79,50 Rotas e Trilhas. Retrieved on April 07, 2009.