Airfare Classes, tickets rules, restrictions and tips

Airlines have 3 travel classes: Economy, Business and First class.
Within each travel class there are different fare classes, indicated by letter codes and relating to ticket or reservation restrictions. Passengers within the same travel class receive the same quality of accommodation; however, the price or restrictions they face for that accommodation will vary depending on the fare class.
Fare classes may also vary by how far ahead the ticket must be purchased, or how long the length of stay is. For example, full fare economy class passengers (Y) are usually able to make changes to their reservation, while discount economy class passengers in the lowest booking code usually have tickets that are non-refundable, non-upgradeable, or non-changeable without a fee.

Economy class codes:
- Full fare: Y, B
- Standard fare: M, H, N
- Special or discount fares: G, I, K, L, Q, R, S, T, U, V, W, X

Below are some examples of our engine participating airlines and their economy classes starting with lowest:

AA - American Airlines: cons. Q, N, G; published S, N, V, L, M
AC - Air Canada: consolidator N, K ; published N, L, Q
AF - Air France: consolidator Q, L, V, T; published N, Q, L, V
AI - Air India: consolidator G, V, M, L, K, H, B
AS - Alaska Airlines/Horizon Air:published T, K, V, L, Q
AY - Finnair - Finland:consolidator O, T, P; published Q, L
AZ - Alitalia - Italy: consolidator N, T, V; published L, N, T
BA - British Airways:consolidator S, L, M, T; published Q, M, K, H
CO - Continental Airlines: published T, S, L, Q, V
DL - Delta - USA: consolidator L, K, Q, H; published U, L, K

Lowest class economy consolidator rules, conditions and tips (unless otherwise specified):

1. Capacity limitations: the number of seats available on a given flight for a specific class will be determined by the carrier best judgment.
2. Flights departing on Monday, Tuesday, Wednesday and Thursday usually offer the lowest fares (midweek fares). As a rule it's more expensive to fly on a weekend than a weekday (25 USD more each way).
3. Advance reservation and ticketing: reservations are required at least 7 days before departure and ticketing must be completed within 3 days after reservation.
4. Most low fares require that you stay over at least one Saturday night before your return flight (or minimum stay 3 days).
5. Maximum stay: return travel must commence no later than 30 days after departure. 3 or 6 month tickets are more expensive.
6. Stopover: none
7. Prices shown are for e-tickets. Paper tickets require additional fees.
8. Cancellations: ticket is non-refundable. Ticket may be refunded or used toward the purchase of another ticket if due to illness/death of passenger or traveling companion. A valid medical certificate or death certificate required.
9. Changes: if permitted, 250 USD for reissue. Fee may be waived in case of illness/death of passenger or family member. A valid medical certificate or death certificate required. You also may be required to pay a difference in fares, if your new flight costs more than the original. You cannot change the name on an airline ticket or give the ticket to someone else to use. Also, you cannot exchange a ticket from one airline to another.
10. If you should find a lower fare after purchasing a non-refundable ticket, Kaven Travel will not be able to issue a credit for the difference in price.
11. Seasonality for transatlantic routes (US to Europe):

Air France and Delta:
Low Season: 25 Dec - 31 Mar and 30 Oct - 11 Dec
Shoulder Season: 1 Apr-15 May, 5 Sep-29 Oct and 12 Dec-24Dec
High Season: 16 May - 4 Sep

Air New Zeeland:
Low Season: 25 Dec - 31 Mar and 29 Oct - 13 Dec
Shoulder Season: 1 Apr-15 May, 10 Sep-28 Oct and 12Dec-24Dec
High Season: 16 May - 9 Sep

British Airways:
Low Season: 24 Dec - 23 Mar and 23 Oct - 17 Dec
Shoulder Season: 24 Mar-25 May, 4 Sep-22 Oct and 18Dec-24Dec
High Season: 26 May - 3 Sep

Lufthansa, Austrian, United:
Low Season: 25 Dec - 24 Mar and 27 Oct - 11 Dec
Shoulder Season: 25 Mar-15 May, 8 Sep-26 Oct and 12Dec-24Dec
High Season: 16 May - 7 Sep

Swiss:
Low Season: 25 Dec - 31 Mar and 27 Oct - 11 Dec
Shoulder Season: 1Apr-15May, 8 Sep-26 Oct and 12 Dec-24 Dec
High Season: 16 May - 7 Sep

Northwest, KLM:
Low Season: 25 Dec - 31 Mar and 27 Oct - 11 Dec
Shoulder Season: 1Apr-22 May, 4 Sep-26 Oct and 12 Dec-24 Dec
High Season: 23 May - 3 Sep