Longest nonstop flights in the world

(1) Hong Kong-Heathrow

Distance: 21,602km

Time: 22 hours and 42 minutes

Airline: Boeing

Overall rank: 1

Boeing launched a test-flight from Hong Kong to Heathrow airport in London in November 2005. This is the longest ever non-stop test-flight in the world.

(2) Changi-Newark Liberty

Distance: 15,263km

Time: 18 hours

Airline: Singapore Airline

Overall rank: 2

Singapore Airline's flight from Changi airport in Singapore to Newark Liberty in New Jersey, United States, took 18 hours of non-stop flying to complete the journey. The carrier discontinued the service last month.

(3) California-South Australia

Distance: 13,840km

Time: 23 hours and 23 minutes

Airline: Unmanned aircraft

Overall rank: 3

An unmanned aircraft flew nearly 14,000km from California, United States, to South Australia. This is the longest flight by an unmanned aircraft.

(4)Sydney-Dallas/Fort Worth

Distance: 13,790km

Time: 15 hours and 10 minutes

Airline: Qantas

Overall rank: 4

Qantas's flight from Sydney, Australia, to Dallas/Fort Worth airport in Texas, United States, takes more than 15 hours of non-stop flying.

(5) Tambo-Hartsfield-Jackson Atlanta

Distance: 13,527km

Time: 16 hours and 55 minutes

Airline: Delta

Overall rank: 5

Delta's flight from OR Tambo airport in Johannesburg, South Africa, to Hartsfield-Jackson Atlanta in Georgia, United States, flies for more than 13,500km non-stop.