I was reading some of the other questions in the forum and came across some mention of the Tambor airport being shut down through or until the 27th of March.
I called Sansa and spoke to their representative. They are on flying out of SJO on normal schedule, but flying to another "local" airstrip, and then providing ground transportation back to the Tambor airport. Likewise, on the way back, the instructions I was given is to meet 1 1/2 hours in advance of your flight time at the Barcelo resort near Tambor airport for ground transportation to the airstrip and the flight back to SJO.
A small inconvenience to get to enjoy the countryside.
Best of luck to all in your travels.