Airlines Are Running Out of Flight Numbers, and They Don't Know What to Do

Clearly the successor solution is to use eight groups of four hexadecimal digits each, separated by colons. Then each individual seat and peanut could be addressed to it's final destination.

More seriously the solution suggested of giving the 3 companies other unused prefixes like D* U* and A* to use with their codeshares and non rev flights to start seems the easiest.

> Here’s the full answer, along with how they triage the problem – for instance by assigning the same flight number to more than one flight a day (although that means they need for it to be flights that would never both be in the air at the same time, such as where the same plane is used and can’t reasonably be substituted)

This sounds like it's calling for trouble!

Whenever I hear that any IDs could be "recycled", I make a mental note to replace the person making such a proposal from all teams that I am involved in.

The worst is I once was put to work on a system where they even recycled GUIDs... I thought "which part of GUID do you not understand, the G part or the U part?" (from which it follows they also don't really understand what ID means)...

I love that so many people here think they can think about the problem for 10 seconds and come up with a solution that hasn't already been considered a thousand times and discarded.

I don't even understand the point of code-share flight numbers. The first thing I do when I see one is look up the original flight number. Most flight search engines will also show you the original carrier.

Why not just get rid of them and book on the original flight number? Is it needed somehow in their systems to know how a flight was booked or what flights are eligible? Can that be fixed instead of the flight numbers?

Many years ago, I worked on a trading floor.

The legacy trading system (X Windows/Solaris/C++ based) was originally written in a time where market volumes were low so you couldn't have more than 10,000 orders (due to a limit on the size of the order id field).

As volumes increased in the late 2000's, there were days where we were in danger of running out of orders ids.

The fix? The system generated order ids 7 days a week even if trading only happened 5 days so we "borrowed" order ids from Saturday.

> Except they don’t. American Airlines, Delta, and United are running out of flight numbers, and nobody knows what to do about it.

All of the above mentioned airlines are the size they are because of mergers.

Why don’t they use the IATA codes of the airlines they absorbed. For example Delta merged with Northwestern. In addition to DL, they could also use NW. American merged with USAirways. They could use US in addition to AA. United merged with Continental. They could use CO in addition to UA.

I'm remembering the ISBN switch, which I thought would throw off some older systems—and it probably did, but it took so long to happen that the transition ended up being pretty smooth. The key element was that for a solid ten years or so, every book had both an old-style and a new-style ISBN (and possibly some still do).

I'm hoping that behind the scenes they really are looking at a better plan than just "work around it", but the workaround can buy them time; and if their operations plan is strong, they'll be able to roll it out very slowly in parallel while all their back-end stuff gets upgraded. (This would require some aspect of the new system to make it immediately distinguishable from the old one, e.g. three-letter airlines or whatever, but that's a minor detail compared to all the other stuff they'd have to work out.) Bonus points if knowing the "old" number lets you algorithmically derive the new one somehow, and vice versa, to make the transition period easier. :)

The entire aviation industry feels like it is in need of a tech stack 100% rebuild.

Systems like Sabre are 60+ years old.

In 2010, Indian railways switched from a four-digit numbering system to five digits.

They were running out of train numbers.

Indian railways today operates 13,000 trains daily.

There is a PDF that talks about the problem, the solution, exceptions, and a rollout plan.

One fine day, IT systems seamlessly transitioned—-took some time to wipe the old numbers from passengers memories.

Wouldn't the easy solution be to use two sets of letters for IATA coded flights for the same airline?

Something like "DL1234" and "DZ1234" for Delta?

I know a lot of the two-letter codes are claimed too, and I'm sure there must be some reason this wouldn't work OK, but it would seem like they they would each have at least one code left over from the various airlines they've acquired over the years?

If an American Airlines regional flight started with "TW1234" again, for example, I don't think it would break the world.

If it's a problem for only 3 airlines in the world, give them a new two letter code, if there are any of those codes left. So airline AA will start using also code ZZ for some of their flights. Travelers will be a little puzzled at first but they'll stop noticing soon.

I sorted the airlines by two letter codes [1] and the list is pretty busy but hex 20 for Space is still available.

[1] https://en.wikipedia.org/wiki/List_of_airline_codes

Give the flights a 128 bit number, so we can give each grain of sand on Earth its own flight number.

I get constantly baffled at the amount of technical debt that goes on in civil aviation.

The fact that no one just overhauls the system with backward compatibility and sets a deadline for the migration, is just insane for me. All these specific problems are solved, and in production (in freight for instance) for more than 2 decades now. But aviation just goes on with their 70s system.

I remember my wife was on a charter flight with 3 initial letters many years ago (in Europe). And when I tried to look up the arrival, many systems could not handle the flight number.

Now slightly unsure whether I did not dream up the whole episode, I did a web search and found https://travel.stackexchange.com/questions/157429/what-is-th...

So IATA seems to have formally introduced that in 1994. (Whether they have abandoned it again later I don't know.) So big airlines could just get a additional 3rd letter(s). The first 2 would not have to change, which makes it easier for humans.

I hate out-and-back flight numbers (where they reuse the same flight number for a flight and for its reverse). It makes it really confusing to actually find the flight status and such.

Separately I also find code-sharing slightly confusing, especially if you're trying to find out who's actually operating your flight for things like checkin counter, etc.

You can do it like Easyjet. They have normal easyJet EZY, easyJet Switzerland S.A. EZS, easyJet Europe Gmbh EJU. Problem solved. OK they have a lot fewer planes than United but 99% of their flights are short (<3h) so they probably need similar number of flight numbers

Code-sharing is a headache for customers. Trying to find your flight on a rotating screen is frustrating, and having a different flight number on your ticket compared to the actual flight is just confusing. We should do away with code-share numbers and use the operating airline’s flight number instead.

Obviously the solution is airline code + iata source airport + iata dest airport + airline scheduled flight # for the day/week

UA-LGA-LAX-001

LH-LHR-FRA-012

/obviously/

Anyone who’s worked doing any kind of IT for the aviation industry knows how much of a clusterf*ck the spec for PNR is. Flight codes are the least of the limitations there.

Using Hexadecimal instead gives over 6.5 times as many possibilities in the same 4 characters - should be more than adequate.

I know airline systems have a lot of legacy code so it might be difficult, but at least logistically (having adequate space to print / display them), and for humans to deal with it's not too difficult.

I wonder if I see an earlier version of this problem - I take the flight BA988 from London to Berlin a few times a year, and in some systems it will appear as BA0988 - possibly because some can handle 3 digit and some neee 4 digit flight numbers.

> assigning the same flight number to more than one flight a day (although that means they need for it to be flights that would never both be in the air at the same time, such as where the same plane is used and can’t reasonably be substituted)

I thought this was already common on a lot of airlines. For example, tomorrow, Southwest flight 1861 goes from MDW to DAL from 1:55pm to 4:10pm, then from DAL to SNA from 4:50pm to 5:55pm, then from SNA to PHX from 6:30pm to 7:50pm. I was on two legs of a similar flight a few years ago, and I didn't even have to get off the plane at Love Field.

The headline is a bit misleading. Because it's not "airlines" in general, but:

> and it’s really only a problem for three airlines in the world.

A lot of the software used to coordinate this stuff is very ancient at this point. The fix is straightforward from a technical point of view but super complicated to implement because it involves replacing/fixing half a century old software systems in use in thousands of companies across the industry. Probably a lot of cobol and other crap that is still in use for this.

Record-oriented storage and SABRE strikes again!

Part of the problem is codesharing, you have to use two flight numbers for the same flight. The whole practice is confusing and I don't think it should be allowed, except in the rarest of circumstances. The seat quality is also suspect at best, when you're not directly buying from the operating carrier.

Why are they bothering passengers with flight numbers?

If computers were like airplanes, programmers would show pointers to users.

What would stop the airlines to use more than one airline code? For example for American Airlines not only to use flight numbers like AAxxxx but also ABxxxx. AB is assigned to Air Berlin, which went out of service in 2017.

Edit: A1 seems to be unassigned, which might be even better, to not create confusions.

Maybe, just maybe the solution is to stop flight code sharing. Having one flight under different numbers is confusing at best and feels misleading. Just imagine giving airlines more space to spam everyone with a magnitude more numbers. Just picture announcement boards at airports…

> So for us, and other two big competitors, we found workarounds for it. And I think the technology investment would be too great…

The is where we all say “not my problem” and don’t give it another thought. Don’t waste your time on these guys.

Maybe the opportunity to raise price really high and save the planet

I like how everyone is looking for technical solutions, where the trivial one is to reduce the number of flights.

It's not like we're not in a climate crisis after all.

They already have a better solution. Did you see AAA777 to Las Vegas. So they are able to add alpha to numerics, when needed. Return flights sharing the number? Why not.

This software is goign to have a REAL problem in 2038. If they can't add a single digit field, they are going to have a problem with time_t.

I wonder if they have enough 2 digit letters to expand their usages.

Perhaps American Airlines could have both AA & AB, so they would then have 20k flight numbers to use?

Can they switch to a radix of 36 instead of decimal numbers ?

Too much consolidation? Time to split up them again?

It won't be a problem soon as airlines worldwide will obviously be scaling back flights due to climate change, right? ;)

/s (just in case)

The biggest challenge here isn't the tech/standards problem.

It's what this signals for the future of the planet's climate.

"Four digits ought to be enough for everybody!" ... looks down at his hands...

IPv6 is the answer: now boarding to Salt Lake: DAL:1050:0:0:0:5:600:300c:326

That's easy: fork the airline. Or have you run out of 2 letters too?

Stupid here, but how hard is to change it to alphabumerical?

5 digits instead of 4?

give the really big airlines some numeric codes that start with the right number. For example, give Delta D7 as well. Then they can have DL1234 and D71234 etc

> The computer systems airlines use are built on top of systems that are built on top of systems that date back sixty years.

It means it’s the time to upgrade the system.

They need NAT!

Switch to hex.

if they re-use the flight number maybe they can add a letter suffix to it. e.g. 1555B?

Someone introduce them to IPv6

Hexadecimal?

how about they help jumpstart the economy and hire engineers to fix the problem?

This is the tipping point that will make the world switch from passenger flights to high-speed rail.

Time for hexadecimal.

I have carefully read the entire thread and nobody has said the answer yet.

Blockchain Ai.

"Oh no"

* adds a 5th digit

I generally know better than to read the native comments on articles like this, but I've not really woken up yet. Are those merely stupid when they suggest using alphanumeric, or are they abominably stupid because the backend only allows numeric codes?

they're going to have to NAT them

Yeah, it's like the time the NASDAQ first had more than 65535 tradeable things.

Just give each airline another prefix UA1234 -> UN1234.

Can they have another prefix in addition to "AA"?

Sounds like a great opportunity to limit the size of an airline and promote competition: each airline can't have more than 10,000 registered flights.