Numerals Latter parts of the fare basis Numerals often indicate the maximum stay the fare rules will allow at a destination. Thus a YE45 is an economy excursion fare with a maximum stay of 45 days. Similar patterns could be YE3M indicating a 3-month maximum.[1][2] H or L Other than first letter High or low season[5] W or X Other than as the first letter These two letters are commonly used in airfares to state if a fare is valid on a weekday (X) or restricted to weekends (W).[5] The specific days of a weekend may vary, and can include Friday travel.