LAN uses the following table to demonstrate which fare group codes can be upgraded with coupons.



But when searching for flights on booking sites, AA.com, Matrix etc. It always shows the single letter fare class rather than the LAN rate group code. I am going to attempt a "ready reckoner" that maps fare classes into upgradeable flights.

If any of it is wrong can you let me know, then I can leave it here for myself and anyone else that finds it useful so that I don't have to look it up each time I want to book a flight.

Fare classes in premium cabins (not upgradeable on a two cabin class flight)

Premium Economy P, W (A320 family)
Premium Business C, D, I, J (B767 and A340)
Already upgraded U

Fare classes upgradeable with elite upgrade coupons (LAN rate groups LE, FX and FF)

Y, B, H, K, L, M, V and T (Economy reward travel)

Fare classes not upgradeable with elite upgrade coupons (LAN rate groups CK and SP)

G, N, O, Q, S, X*

Fare classes upgradeable with LANpass kms

Y, B, H, K, L, M, V, G, N, O, Q, S, X*

*X added to these fare classes, it seems to be an even deeper discount than O spotted on LA LIM SCL and XL GYE MAD