There are two options to fly to the venue: Tallinn or Riga airport
Pärnu is about 120 km from Tallinn airport and there is quite good bus connection,
From Tallinn to Pärnu main busstation (in estonian „bussijaam“) http://peatus.ee/#route_search;33183;80261/eng
From Pärnu to Tallinn main busstation http://peatus.ee/#route_search;80261;33183/eng
From Tallinn Airport to the Tallinn Main busstation is 5 min by taxi.
If you like to use Riga Airport (about 190 km from Pärnu but sometimes is cheaper and better arrival and departure times) then there is Lux express homepage where you can look the bus connections (http://www.luxexpress.eu/en/tallinn-riga) The bus stop name is Parnu coach station.