399.37—Joint fares.
There should be joint fares in all markets over all routings within the contiguous 48 states and the District of Columbia as follows:
(a) Level.
The level shall not exceed the sum of the maximum local fares permitted by this subpart minus one tax-rounded coach ceiling terminal charge for each interline connection, and in any event shall not exceed the sum of the actual local fares.
(b) Division.
Joint fares shall be divided according to the relative costs of the mileage flown by each carrier participating in the interline movement. However, where a joint fare is equal to the sum of the actual local fares, each carrier shall get the local fare as its share.