Travel time from Naples airport to Amalfi

It depends when you will be travelling. You could take the Alibus from the airport to Naples and take the SITA bus from Naples to Amalfi.
http://www.sitabus.it/sitabus/campania/orarioCAMPANIA/QUADROXIII.pdf But in summer, you could also ferry from Naples to Amalfi. Curreri Viaggi runs a bus from the airport to Sorrento and SITA runs bus service from Sorrento to Amalfi, but again there is ferry service from Sorrento to Amalfi in summer. You could also take the Alibus to Naples and take the train to Salerno and ferry the coast from Salerno in summer, or take the SITA bus at other times.

Where on the Amalfi Coast are you going? Vietri sul Mare? Cetara? Maiori? Minori? Atrani? Amalfi? Praiano? Positano? Sorrento? IMO, these are the most efficient ways to get from the NAP airport to the Amalfi Coast: 1. If going to Salerno, Vietri sul Mare, Cetara, Maiori, Minori, Atrani or Amalfi: take the SITA airporter bus direct to Salerno, then connect to the regular SITA bus bound for Amalfi (the airporter bus to Salerno does not run on Sundays). On Sundays or if the airporter bus schedules to Salerno are not convenient, take the Alibus airporter bus into central Naples- Piazza Garibaldi, then connect to the direct SITA bus bound for Amalfi. You could also take the Trenitalia train from Napoli Centrale to Salerno, then connect to the regular SITA bus bound for Amalfi, or take the Cooperativa Sant'Andrea ferry boat (April through October) from Salerno-Concordia Dock to Amalfi. 2. If going to Sorrento, Positano or Praiano: take the Curreri airporter bus to Sorrento, then connect to the regular SITA bus bound for Amalfi (which stops at Positano and Praiano). This service runs daily including Sundays. www.curreriviaggi.it www.sitabus.it www.metrodelmare.net www.coopsantandrea.it www.ferroviedellostato.it You could also go into central Naples - Piazza Municipio with the Alibus airporter bus, then take a Metro del Mare hydrofoil from Molo Beverello to Positano or Amalfi, but the boat service is not very frequent, is expensive, and does not operate during the late autumn, winter or early spring.

Amalfi is the destination--thanks for all the help so far.

You have three options, the Alibus from the airport to Naples and the bus from Naples to Amalfi; the bus from the airport to Salerno and the bus or ferry from Salerno to Amalfi; the Alibus to the train station in Salerno and the bus or ferry to Amalfi.
http://www.sitabus.it/sitabus/campania/orarioCAMPANIA/Salerno-Capodichino.pdf