Airlines are running out of flight numbers and don’t know what to do about it

Airlines are running out of flight numbers and don’t know what to do about it

by Gary Leff August 3, 2024

Airlines use up to four digits for flight numbers. That means they can offer up to 9,999 flights (since there is no zero flight), and none come close. American Airlines operates about 6,700 daily flights, including its American Eagle regional services. So it should have plenty of room to grow!

But that’s not the case. American Airlines, Delta and United are running out of flight numbers and no one knows what to do about it.

In fact, this topic came up at an American Airlines employee meeting last week. After the airline’s second-quarter earnings call, executives were chatting with employees and answering their questions. One IT employee raised the question: “We’re running out of flight numbers. Should we consider a 5-digit solution or something else?”

Brian Znotins, the airline’s senior vice president of network planning, outlined the challenge and the steps being taken to address it.

• In fact, they have over 9,999 flights they want to put their flight number on.
• This is because they have partners with whom they share codes. They want to sell American Airlines “flights” from Doha to cities in India and Pakistan, for example. They want to sell American Airlines flights operated by Alaska Airlines.

Here’s the full answer, and how they deal with it, such as assigning the same flight number to multiple flights per day (even if that means they have to be flights that would never both be in the air at the same time, such as when the same aircraft is used and cannot reasonably be substituted):

With industry consolidation, airlines are running out of flight numbers. … (Codeshares have caused us to run out of flight numbers.) We have over 9,999 flights that we would like to number. To conserve flight numbers, we have a model that allows us to keep flight numbers so we can continue to add them where we want. Our regional partners… we have to add ranges of flight numbers for that.

Believe it or not, there’s a whole body of work that revolves around flying numbers, and it’s not just the 1989 Kansas City Super Bowl number.

Needless to say, the actual answer to the question is that we do return flights and we also do what is called a ‘return flight number’, where a flight going to a hub will have the same flight number as the flight returning to the hub, and that too so that we can maintain the flight numbers.

Technically, we’re working with systems that are from the 1960s. We have two-letter airline codes and four-digit flight numbers. If you remember, you can think of this as a Y2K problem. It’s extremely difficult to find ways to add an extra digit to that field, and this problem really only affects three airlines in the world. Other airlines don’t have this problem.

So for us, and for our two big competitors, we have found workarounds. And I think the technology investment would be too big…

The computer systems that airlines use are built on systems that are built on systems that are sixty years old. So it’s hard to adapt to that. And, like Y2K, the older systems have economized on data size for storage and processing reasons. Abbreviations have been used. For example, that’s how United Airlines’ elite status levels got their name, “1K” was used instead of 1000K or 100,000 miles because they only had two numbers to denote it. This was an internal tag, not meant to be made public to customers, but it ended up sticking.

In April, American Airlines changed the number of its flights so that the number of mainline flights increased not only from 1 to 2,999, but also to 3,139.

They also always have fun with flight numbers, for example flying flight 1776 from Philadelphia to Boston, flight 1492 to Columbus, AAA777 to Las Vegas and flight 420 to Denver.

And American Airlines CEO Robert Isom responded to the question about limiting the number of flights by noting that “we aspire to be much larger, so over time, let’s put that on the table as a project.”

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