From FlyerGuide Wiki

[edit] Fare Codes

American Airlines fare codes are used by American Airlines to identify the features of the various fares offered.

[edit] Deciphering a Fare Code

• First letter: booking class (except for UP fares - YUP books into A and KUP books into P). See Inventory Classes and Mileage Eligibility (AA).
• First number (other than 26): domestic: advance purchase requirement. If it is 0, same day ticketing is allowed, but waitlisting is not.
• Second number: minimum stay requirement
• Third number: maximum stay requirement
• A: one-way
• R: round-trip
• AP: advance purchase
• BIZ/BZN: instant purchase non-refundable fares for business travelers--no Saturday night stay requirement, 30-day maximum stay
• FS: flight-specific
• J/JFK: JFK only
• N/NR: non-refundable
• Z: restricted, which may mean confirmation required (possibly refundable though)
• AA: Web-only fare
• UP: instant upgrade into different booking class

• GB: originate in GB, following number is year of fare applicability
• US: originate in US

• E: minimum stay requirement (Saturday unless overridden by second number)
• M: Saturday stay requirement (second number becomes maximum stay)
• C: next number is change fee

• Second position:
  • P: peak season
  • H: high season
  • K: shoulder season
  • L: low season
  • M: other seasonal restriction

• Third position:
  • W: Sun 12:01a-Mon 11:59a, Thu noon-Sat 11:59a
  • X: not on Fri or Sun
  • B: weekend (Thu/Fri-Mon, no Sun with X)
  • S: midweek (Tue-Thu or Tue-Wed, also Mon with X)
  • F: specific times (e.g. daily 8:45a-9:45a)
  • O: specific times and dates (e.g. Tue/Wed 8:45a-9:45a)

• LV: Applies to any flight except to/from/via DFW and applies to any flight to/from/via DAL.

• A: advance ticketing required
• R: reservation confirmation required
• D: ??? (appears on shorter flights, and some long flights)

• Last position:
  • S: fuel surcharge
  • G: restricted day of first travel
  • X: restricted day of first travel

[edit] Related Flyertalk threads

• Guide to AA fare basis codes. Thread started July 24 2003.