The logic behind AA flight numbers
 

Hi!

I’m primarily a BA flyer based in London, but I’m heading Stateside in 2 weeks, and have quite a few domestic flights on AA lined up. Putting all my flights into my diary, I thought I’d made a massive booking error. At the end of August, both my DFW-ICT and ICT-DFW a few days later had the same flight number, AA 2407. How was that possible? Had I booked the same flight twice? After a bit of a panic, double checking all my reservations, I worked out that the same aircraft goes DFW-ICT-DFW with a single flight number. Doesn’t having AA 2407 with an identical departure and origin city cause any issues? I can see why a multi-sector flight would have the same number, but not a “there-and-back”.

To further confuse things, if you booked AA 2407 for today, you’ll be flying DFW-BOS! Why the need to change flight numbers? I recall flying BA 727 many, many years ago back from Geneva on a ski trip (I’m sure you can guess why that flight number stuck in my head!). I just put that into Google, and BA 727 is still a midday GVA-LHR flight.

Finally, why do flights on the same route have such radically different flight numbers? On BA, you generally have consecutively numbered flights (e.g. LHR-LYS has three daily flights, BA 360, BA 362 & BA 364), or at least stay within a fairly small range. On the day I’m flying ORD-MSP, in time order, the flights are AA 1405, 2455, 1409, 47, 1559, 2185, 4713. I mean, where is the logic?

So, this isn’t a griping post, i'm just wondering if anyone can explain how the numbers came about!

Thanks :)

I've wondered about this as well. It seems to be worse post-merger too, with flight #'s changing on a regular basis.

Part of me wonders if they do this to game the on time % numbers or something - do those stats reset when AAA/BBB flight gets a new #?

When AA and US merged, there was a bit of a 'crunch' on flight numbers and AA needed to combine some legs in order to have enough flight numbers. At that time, AA chose to make a good number of AAA-BBB-AAA flights as well as increased usage of AAA-BBB-CCC flight numbers (especially adding domestic segments to international flight numbers). Why AA didn't opt for more of the AAA-BBB-CCC variety rather than doing so much AAA-BBB-AAA I can't say. Doesn't seem to harm anything, though it does drive confusions for fliers every once in a while.

As for flight numbers changing, I've noticed this on AA and all the US majors. Every few months a lot of flight numbers will swap out. I've always speculated that that this is intended to reset 'on-time numbers' for the flight but I could be totally off base.

AA and the US majors don't really use consecutive flight numbers in any organized manner like BA does. There are some (non-binding) numbering patterns that have emerged (many ORD-LGA are in the 300s for example) but it's just not something the US majors tend to focus on in general.

Well, it does harm flyers, because a single flight number for AAA-BBB-CCC gets treated as if it were AAA-CCC for the purpose of computing base miles (and therefore MM and EQM but not RDM any more). The silver lining, such as it is, is that it often means fewer stickers needed for upgrading.

Should be able to call and have the segments 'divorced' at least I know it's possible to do this on Delta. Can't remember if I've ever done it on AA or not.

Keep in mind that there aren't 9,999 AA flights, but with codesharing, several flights have multiple numbers in the system. Delta does the AAA-BBB-AAA same number system on many of their flights as well. US used to do this on some of their express flights - not sure why as I'm sure there were plenty of numbers to go around back then. But I do recall seeing that I was checked in as sequence 75 on a 50-seat flight once and that confused me (because the first 50 were on the inbound flight and I was on the outbound).

I remember reading that Air Traffic Control systems can't handle numbers above 9999.

I guess there must be an internal hard-coded limitation as well. Otherwise, the logical solution would be to use a fifth digit to designate codeshares. For example, flight 1XXXX could be the AA codeshare of BA XXXX, 2YYYY could be the AA codeshare of IB YYYY, etc. This would enable AA to use the full 9999 numbers, and it would make things much clearer for travelers on codeshares as well, because those who knew the system wouldn't have to keep track of 2 flight numbers.

When the original Guide to PHL was created (legacy US), we included this as primer for flight numbers:

West Side US Airways 0001 - 0699
East Side TATL 0700 - 0799 Also some domestic thru flights
East Side Us Airways 0800 - 2199 Including Shuttle flights
PSA Airlines 2200 - 2599
Mesa Airlines 2600 - 2999
Chautauqua Airlines 3000 - 3099
Republic Airlines 3100 - 3499
Trans States Airlines 3500 - 3550
Air Wisconsin 3551 - 4099
Piedmont Airlines 4100 - 4649
Colgan Air 4650 - 4849

So part of it was legacy HP, part of it was legacy US. It certainly doesn't go into the logistics of wildly different flight numbers like your ORD-MSP example, but I think as different airlines are absorbed into the "main" carrier, you still see remnants of those old flight numbers.

Are there really more than 9999 AA coded flights? That number seems high.

Still, the issue with me isn't so much the AAA-BBB-AAA being the same flight #, but the numbers just flat out changing. I also think AAA-BBB-CCC should not all be on the same #, but that's just me. I have a trip at the end of August, booked in mid July, with 5 segments. Of those 5, none of those flight numbers exist today for those city pairs.

Looking at the next trip I am booking today, for travel in early October, 6 segments, 2 of those do not exist today under the flight #'s shown.

Far fewer than 9999 flight numbers are actually available.

9xxx flight numbers are not for regularly scheduled passenger flights (but may applied to a normal passenger flight that's been rescheduled in a way that the original flight number would have been ambiguous, for example flight AA1234 is delayed to the point where another flight AA1234 is also flying somewhere else in the system by that point).

Numbers above the first few thousand are reserved for regional jet flights and codeshare flights.

So there's only a few thousand flight numbers are available for AA's own metal mainline jet flights.

A note in the aircraft help desk states:

"NOTE: At this time, AA Flight numbers 400-899 and 1651-2174 indicate LUS equipment/crew."

Different series indicate code shares operated by other airlines, charter flights, etc.

And for agents. Apparently there have been increased instances of agents mistakenly informing passengers that their flight has been delayed or cancelled because they misread the flight information for an "out and back" flight number.

I would prefer if they took the LUS approach and had more AAA-BBB-CCC where it's actually the same airplane flying both legs.

Maybe once the flight number ranges are fully integrated we'll have more logical flight numbering.

I'm wondering what happens if you take AAA-BBB-AAA with same flight number...

I've seen this over and over in my job the last 20 years. Well intended "smart" numbering leads to ridiculous results. No different in this case where many of these flight numbers come from the logic listed above.

Prior to the merger, legacy AA used odd flight numbers for flights heading west and south; north and eastbound flights had even numbers.