Order from highest to lowest:
J, C, D, Y, S, M, B, T, H, V, W, Q, L, N, Z, ZED

J - Full Fare Business Class, no advance purchase required.

C - Upgraded Business Class or Discount Business Class on selected routes (YYZ-HNL...). This is also used as upgrade inventory.

D - Award Business Class

Y - Full Fare Economy Class, upgradeable for all tiers with the appropiate certificates at the appropiate time before departure.

S - Super Comfort Class. It's available on routes which they do not distinguish between J & Y. (YYZ-MAN/GLA...) You can pay more to buy S class so you get a J seat but Y service.

M - Close to full fare Economy Class. Elite can upgrade M fares on all AC flights except to Europe; SE can upgrade M fares on all AC flights at 7 days prior to departure; E at 72 hours; P can upgrade M fares on domestic flights at 24 hours.

B, H - Discounted Economy Class. Elite can upgrade on these fares for domestic and transborder flights (exclude HNL); SE can upgrade on these fares for all AC flights at 7 days prior to departure; E at 72 hours; P cannot upgrade on these fares at 24 hours. H has advance purchase of 7 days on domestic flights, 7-14 days or more on transborder flights and 0-14 days on international flights. B has advance purchase of 3 days on domestic flights, 7 days on transborder & international flights.

V - Discounted Economy Class. Not upgradeable but same day standby allowed. Usually has advance purchase of 7 days for domestic destinations, 14-21 days for transborder and 7 days or more for international destinations.

[Some international V & H requires no advance purchase such as JFK-HKG...]

T - no longer available (except on YYZ-YHZ & eastern triangle routes); introduced earlier in the year to compete with RootsAir; was basically tickets with 3 or 10 days advance purchase which allowed changes to it and no Sat night stay required. Non upgradeable. Goes after B in the order of the fares.

W - Award Economy Class.

(Most of the discounted fare on the western and eastern triangle routes have different advance purchase requirements ranging from 10 days to 0 days.)

==Standby allowed on the above fares==

Q, L, N - Discounted Economy Class. Not eligible for upgrades by any tiers; No standby allowed. Usually 14 days advance purchase on domestic flights & 7 days or more on transborder and international flights. There are some L fares (FLEX fares) which have no change fee and allow you to standby for an earlier flight. (They're bookable here - http://www.aircanada.ca/specials/jazz_e/ )

Z - for tour wholesalers (such as cruise lines or AC Vacations) where the airfare is sold as part of a tour package. Not eligible for upgrades by any tiers; No standby allowed. No Aeroplan points.

ZED - Star Alliance employee travels.
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