The Secret Lives of Flight Numbers

Jet Blue from JFK to Las Vegas: flight number 711.

I’ve noticed at least one flight where the initial flight and return flight are the same number.

What puzzles me is the few times I've noticed the same flight numbers (same airline) being used on different routes on different days. What's with that?

Forgot to log in first, and my comment was not "conserved".

Regional carriers serving the bigger airlines tend to have blocks of numbers, such as Pinnacle's 6000-series flight numbers.

The article only talks about IATA prefixes. These are used in reservation systems and on ACARS. ADS-B and VDL2 use the ICAO 3-letter format. There are not enough unique 2-character combinations to go around, so some IATA prefixes are duplicated among different airlines.

KLM has frequently used two different flight numbers for the same flight, even on a daily basis. This was not code sharing, because both started with KL. These were mostly transatlantic flights. When displaying the route in e.g. Flightradar, it looked like one flight showed the scheduled path while the other showed the actual path flown. That's just my guess because of lack of a better explanation. Does anyone have any insights why this was happening?

On FlightRadar 24, I’ve caught several Aero Mexico flights to/from same destinations fly past each other; usually over the Southeast US after Midnight or so when traffic is much less there.

I first took AA1 JFK to LAX in the late 60s.

There's the classic 1990s UA1 and UA2. UA1, west-bound JFK-LAX-HKG-DEL-LHR-JFK), and UA2 in reverse. I've been on a few of those segments, although I swear at some point near the end of those flights, they added SFO-LAX as a very short leg. I can't prove it or find it on the interwebs, but I really believe I've been on UA1 SFO-LAX followed by UA1 LAX-HKG, circa 1995.

One of my favourite is AS500, the SEA-IND flight. They've had this flight number ever since starting the route to Indianapolis. In a nod to Boeing's Charleston factory ... they have AS787 for SEA-CHS.

I've always been curious about how flight numbers are determined and sadly this article provides next to nothing to explain it other than east/west designations. So the answer is they're mostly random. Got it. Thanks for wasting everyone's time.

Back before deregulation of the airline industry here in the U.S. in the late 70’s and early 80’s, all the major carriers operated most of the low number flights coast to coast nonstops were odd number and even number eastbound. North and south,odd southbound and even northbound. There were no four digit flight numbers then, with the exception of extra sections during holiday periods, I.e. JFK/EWR-FLL/MIA.

Speaking as a Concorde passenger on one trip, AF001 flew Paris-JFK, and AF002 was the return. Hmmm, glamor and low flight number: a connexion?

Can anyone from SWA shed light on why flights are designated both SWA and WN?

I take great pride in being able to say I flew on QF1.

There is indeed a method to the madness of flight numbers. For example, flights are usually numbered based on their direction of travel. An example, north and eastbound flights are assigned even numbers, while south and westbound flights are numbered odd. Also, once a flight number is assigned to a flight route, that flight number typically remains the same day after day regardless of the equipment assigned to that route. Often a route that is flown between to cities will be separated by one number, ie, flight DL-805 ATL to PDX will be flight DL-804 on its return to Atlanta.

Finnair had a famous (infamous?) flight AY 666 to HEL before changing it.

As someone who follows charter flights of sports teams, Delta charters usually start w/88**, United w/25**, Alaska w/98**, Allegiant w/46**. Right off hand can’t remember what Sun Country, Southwest, or American charters start @.

Just last night, I caught the outbound United charter 2503 for the Chicago White Sox from Seattle to Oakland; pass the inbound Delta charter 8877 for the Atlanta Braves from Oakland to Seattle in Southern Washington state. Delta military charters usually have a 89** or 9*** designation.

sorry..my computer did something and i didnt get to finish/correct the comment!my last sentence was supposed to say,i will always remember southwest airlines because their code is WN,kind of odd,and city codes,such as nashville,is BNA,for which we were told to remember "bananaville"!!!with the exception of commuter flights connected with my airline, which all had 4 numbers,the flights on my carrier were always 2 or 3 numbers,and i was told as well that if a plane were involved in a fatal crash, that flight number was never used again...

..INTERESTING AND FUN ARTICLE..yes those who have been around the airline business for a while have an understading of codes and numbers,partiularly codes because in the classes you receive early on, they "ingrain" these codes as well as city codes into your brain and you have to take tests to see if you learned them! i wil alwyas remember learning al a

Some regional flights have up to three flight numbers. It depends upon the selling airline when it is different from the operating airline. A flight operated by Endeavor could have a Delta number, a KLM number and an Air France number.

Good info for those who are unaware of it... Anyone been in the industry over a few years has probably figured that out! Especially if they have Non-Rev'd