While Zadar is the closest airport to Novalja, flights can be hard to find, whereas Split airport is the largest in the south of Croatia, just a few hours further down the coast. There are lots of good local buses because the area is now so popular in summer that public transport has become very good. But as an idea, this route is probably one of the best:
TAXI TO TROGIR: Trogir is to the west of Split airport – which makes it on the way to Pag – where the town of Split is actually to the east of the airport. A taxi costs about €25-30 for a 4-8 passenger car.
BUS FROM TROGIR TO ZADAR: Search for BusCroatia for exact times, as there are lots of departures but they can be really irregular. You'll pay between €12 and €19m, and the journey takes about 2 hrs 40 mins.
BUS FROM ZADAR TO NOVALJA: This bit's a shorter journey, about 1hr 30 mins at a cost of €10-15. There are not many departures per day, but they are usually well timed with incoming services.