See also the Avignon Tourism website: https://avignon-congres-expo.com/congres-et-seminaires/acces/
Avignon has two train stations: “Avignon Centre,” within walking distance of the Palais des Papes and “Avignon TGV,” which is 5 km outside town and has regular train connections (about twice per hour; 5-min ride) to “Avignon Centre”.
Taxis from "Avignon TGV" to the city center cost roughly 25€
The main airports serving Avignon are:
Marseille Provence Airport (MRS) with bus L040 to “Aix en Provence TGV”, then a 20 minute TGV ride to “Avignon TGV” (about every hour; latest departure from MRS at 20:34).
Lyon Saint Exupery (LYS) with TGV to Avignon, either directly from “Lyon Saint Exupery” (6 trains per day; 50 – 90 min journey; latest depature from LYS at 19:43) or via “Lyon Part Dieu” (roughly every hour; 30-min ride; Rhonexpress + 60 – 80 min TGV)
Paris Charles de Gaulle (CDG) with TGV from “Aéroport Charles de Gaulle 2 TGV” (roughly every hour; total 160-200 min; latest departure from CDG at 21:10)
Avignon airport (AVN) has connections to Belfast, Birmingham and Southampton with flybe.
Nimes airport (FNI) has connections with Brussels-Charleroi, Luton and Stansted with Ryanair.
Maps of (left) Avignon center and (right) Avignon TGV: