What is the LONGEST passenger flight (with a flight number) in the world?

Question

For example, JQ151 from Sydney to Christchurch is around 3 hours. NZ1 however, is about another 7 to Hong Kong.

Will need a regular flight number to verify.

Definition is longest in terms of flight time / distance (they should be linked, logically?).

Answer 1

The longest non-stop (by Wikipedia source) flight is Newark to Singapore on Singapore Airlines flight SQ21 which is and 18 hour 50 minute flight of some 15,345km

However for single flight number, allowing stopover, Things are hard to research. Not many websites list tables of distances by flight number. So I resorted to thinking of a route and then looking on the airline websites to see if it was one flight number or split over two flight numbers.

I suspect the longest route that could be a single flight number and have a stopover would be Northern Europe to Australia. So I searched on several airlines for flights. I found a few contenders (but no definitive answers):

• NZ1 and NZ38, both on Air New Zealand fly London to Auckland with a stop in Hong Kong in 26 hours and 40 minutes. A distance of 18,463 km.

• QF320 on Qantas and BA15 on British Airways fly London to Sydney with a stopover in Singapore. They both take 22 hours and 50 minutes.

• QF1 on Qantas goes from Sydney to London, again stopping in Singapore and is 23 hours and 25 minutes.

Answer 2

From Wikipedia:

Newark - Singapore (Singapore Airlines)
flight number: SQ 21,
15,345km (9,535 miles, 8,285 nautical miles)
from 18 hr 40 min to 18 hr 50 min,
aircraft: Airbus A340-500,
first flight - 29 June 2004

Second place:

Los Angeles - Singapore (Singapore Airlines)
flight number: SQ 37,
14,114km (8,770 miles, 7,621 nautical miles)
from 17 hr 20 min to 18 hr 05 min,
aircraft: Airbus A340-500,
first flight - 3 February 2004

Third place (surprisingly only by distance, but not by time)

Sydney - Dallas (Qantas)
flight number: QF 7,
13,804km (8,578 miles, 7,454 nautical miles)
15 hr 25 min,
aircraft: Boeing 747-400,
first flight - 16 May 2011

Third place by time:

Los Angeles - Bangkok (Thai Airways International)
flight number: TG 795,
13,309km (8,270 miles, 7,186 nautical miles)
17 hr 20 min,
aircraft: Airbus A340-500,
first flight - 28 September 2006

Answer 3

Since the two answers so far will no longer be valid soon, I thought it is time to add a new answer:

Singapore Airlines is cancelling their nonstop flights from Newark to Singapore and from Los Angeles to Singapore. So the longest flight will be Sydney - Dallas by Qantas (QF7).

Answer 4

The longest flight by flight number (including stops) would be Korean Air's flight 062 from Guarulhos Gov Andre Franco Montouro (GRU) in Sao Paulo, Brazil to Incheon Intl (ICN) in South Korea via Los Angeles International (LAX). It is 28 hours and 35 minutes.