You didn't expect me to show up here.
Flights from Panama to Havana are crazy. They are very expensive for a 3 hr flight. All the South American Airlines fly you south then to Havana and the US airlines fly you to the US then Havana. Most of these flights are cheaper than direct flight. I have seen some with 2 stops and take 42 hours. Most of them are between 6 and about 12 hours
Just a transit stop here.