Hello!
Only way directly to Split from airport with a Taxi but if you go to the bus station in Zadar you have Bus to Split in every hour.
It is a site of airport: http://www.zadar-airport.hr/hr/zap_kako.php
bus station: http://www.liburnija-zadar.hr/kolodvor/raspored_linija.php
04:30 PO-NE 76,00 Zagreb-Split Croag
06:00 PO-NE 73,00 Zadar-Dubrovnik Larus
07:00 PO-NE 65,00 Zadar-Split Contus
07:30 PO-NE 65,00 Zadar-Split Puntamika-Line
08:00 PO-NE 73,00 Zadar-Split Larus
09:00 PO-NE 66,00 Zadar-Split Autotransport Šibenik
10:00 PO-NE 73,00 Zadar-Dubrovnik Larus
11:00 PO-NE 71,00 Rijeka-Split Autotrans Rijeka
11:35 PO-NE 66,00 Rijeka-Dubrovnik Autotransport Šibenik
12:00 PO-NE 73,00 Zagreb-Split Larus
12:30 PO-NE 62,00 Požega-Split AP Požega
12:45 PO-NE 76,00 Zagreb-Dubrovnik Croag
13:45 PO-NE 71,00 Rijeka-Dubrovnik Autotrans Rijeka
14:00 PO-NE 66,00 Zadar-Split Autotransport Šibenik
14:30 PO-NE 73,00 Pula-Split Larus-Posa
15:00 PO-NE 65,00 Zadar-Split Contus
15:30 PO-NE 71,00 Rijeka-Split P Autotrans Rijeka
16:00 PO-NE 66,00 Zagreb-Split Autotransport Šibenik
16:45 PO-NE 76,00 Varaždin-Split AP Varaždin
17:30 PO-NE 71,00 Rijeka-Split Autotrans Rijeka
...
attila