It turns out that legacy systems are often interesting when you look at them. There’s an interesting summary of the various numbers you’d find on a boarding pass here.
The e-ticket system is an outgrowth of SABRE. There’s a whole system of locator numbers (six alphabetical characters, such as IXYDBY). There are a number of other related and interesting concepts, such as the Passenger Name Record.
What I want to share are some details about the document or e-ticket numbers. Sometimes these are relatively hidden. With American Airlines, you’ll see these in your booking emails, and I would imagine they are encoded in the barcodes used on boarding passes.
On American Airlines, a seat upgrade might look something like this: 001 0629 793337 (spaces added).
Let’s break it down:
- 001 is the airline code, in this case for American Airlines. I’m supposing that more generically, this might be called a provider code or carrier code– I think it’s possible to have train or other transit providers.
- 0629 is the form code.
- 793337 is the serial number; the specific document in question.
A ticket looks like this: 001 2280 476034. Note that the form code has the form 2XXX.
At least for American, a few examples of form codes:
- 0XXX are add-ons
- 02XX checked bags
- 04XX same-day upgrades
- 06XX seat upgrades (eg 0635)
- 2XXX are tickets
- 7XXX are third-party tickets, such as those booked through Costco Travel or Expedia
As an aside, the AA refunds request site needs these e-ticket numbers to request refunds.