We landed at Zadar airport last summer and used hbtransfer company at price of 20 euro for 3 people.That is the cheapest price i founded, we used them for other transfer across croatia and prices were very affordable, i would reccomend them.
Their website is http://hbtransfer.com/
Average price from Zadar airport to old town is 20 euro but its vary from company,some companies have way higher prices
Taxi in Zadar are cheap compared to here in UK. We took taxi from Zadar to Plitvice lakes and back .On our 10 days trip we took taxi from Zadar to Split and Trogir, and did few short trips to Novalja,Pag,Biograd,Krka national park and Paklenica.For 8 of us it was same price as bus but still more comfortable.
We landed on same airport and used one of taxis in front.some asked for 50 euro, some 40 euro but on end we took cheapest for 20 euro on way back we payed 30 euro
I know travel can be stressful especially than when you not booked your transfer service in advanced. but I know some reputed and professional taxi transfer service providers which can easily drop you from the airport of zadar to split or your desired destination and Johnnie Taxi service is one of them.
Plenty of taxis waiting outside terminal to take u to your destination,no worries for that. Prices vary from 20 euro