How to get to Bari airport from the town of Bari?
Train or taxi
According to the airport website there is a suburban bus#16 run by AMTAB every 45 minutes (cost 1 Euro), also express buses every hour or so run by competing companies - Terravision (they run airport buses around Europe, some doubts on whether still runs) and Autoservizi Tempesta, both priced at 4 euro.
The train costs 5 euro, according to the website, the station being a 10 minute walk away, more frequent service. [now 5.30 Euro]
A taxi apparently is a 23 Euro fixed price.
https://www.bariairport.net/
https://www.terravision.eu/airport_services.html
https://www.autoservizitempesta.it/
https://www.muvt.app/libretto/16-Bari%20Centrale%20-%20Aeroporto.pdf