First class codes
F, A, P, R
On USA domestic flights, F commonly indicates first class on a two-cabin plane. If a three-cabin aircraft is used, P (for "premium") may be used to distinguish the higher level of service in first class. The R code indicated supersonic transport and was no longer used after the retirement of the Concorde, however with the introduction of the new Airbus A380, Singapore Airlines and Qantas have re-introduced the R class to distinguish a higher class than regular First Class. The A and P codes may indicate a first class ticket whose fare is reduced due to restrictions on refunds, advance reservation requirements, or other terms.
The codes in short:
F = Full-Fare First Class
P = First Class (some airlines use this code for Business class. Jet Airways of India, for instance).
A = First Class Discounted
R = First Class Suites (currently only Airbus A380, and formerly Supersonic Concorde),