Cala d'Or is about 75 minutes from Palma de Mallorca airport. The eastern resort of the island can be reached by TIB buses: firstly the #1 to Palma de Mallorca bus station (bus stop is located near the exit of the arrivals hall, fare is 3 EUR) and then the #501 Palma-Cala-d'Or (fare is 8.5 EUR, up to 50% less with Intermodal Card).
For more information on bus schedules and timetables, visit the official company website.
The IB Taxi, Taxi PMI is another way to get to Cala d'Or from the airport. The average cost is 65 EUR (4 EUR boarding, about 1.25 EUR per 1 km).