Split ticketing and exceptions

Split ticketing is a feature that allows travelers to purchase two one-way tickets with separate carriers instead of a single round trip ticket single carrier when booking round trip flights.
The split ticketing option is always enabled but split tickets are only shown when the cost of 2 one-way tickets is lower than the round trip ticket. The one exception to this is IF: 

• the travel is fully within the U.S., within Canada, or between the U.S./Canada AND 
• all legs of the trip are with a single carrier 

Only if BOTH of those conditions are met are split ticketing options not shown. Also, split ticketing options are not available for NDC fares.

Pros

Split ticketing can provide lower ticket prices and greater cabin class and fare options to the traveler (in some cases). 

Cons

It can be more difficult for both agents and airlines to support and service these tickets because there are multiple carriers involved. If something goes wrong, it’s hard to make a single party responsible and it can make it hard to address any traveler frustrations. In some cases, certain airlines may not allow check-in when split ticketing has been applied.