Fare Rules - The Basics

Rule	Explanation
Booking Code	What is the booking class required for booking this fare? Using booking classes, the airlines control how many seats on each flight are available for each fare. e.g. F,P,J,C,Y,B,M,Q,V,H,L
Penalty	What part of the fare, if any, is refundable? Can the value of the ticket be used as a credit for future travel? If so, what is the service charge? What is the change fee? (Must also read Rerouting - See Glossary. You can't always change the ticket for the change fee.)
Res/Ticketing	When must the reservation be made? (e.g. 7,14,21 days in advance) When must the ticket be issued? (e.g. 24 hours after making reservation) Usually the earlier of the two deadlines takes precedence.
Minimum Stay	e.g. must stay over a Saturday night (often stated technically as "return travel valid on the 1st Sun after 12:01 am")
Maximum Stay	e.g. 30 days, 60 days, 365 days
Day/Time	Some fares are only valid on particular days of the week, or at particular times. For example, some fares are valid Mon-Thu only, or from 7 pm - 6 am only.
Season	Some fares, particularly overseas fares, have an associated season (e.g. 15SEP-12DEC). For overseas travel, usually the departure date determines the season for the round trip fare.
Blackout Dates	Some fare are not valid on certain dates - e.g. over a holiday weekend.
Eff/Exp	Effective/Expires: Many seat sale fares must be purchased by a certain date. Find this date in this section of the rules.
Flt Appl	Certain fares are only valid for particular flights - e.g. nonstop only, or flight 123 only.