Just some info for those going from what we found out when we went via Vienna to Maribor since I’ve got the leaflet handy (also really good free tourist city guide book you can get at the train station, very useful)
We got the express city airport train (CAT as they call it), it’s 12 Euro single , 21 Euro return , gets you direct into city centre (Vienna train station (Wien Mitte) in 16mins and from there most Areas pretty walkable / loads of tram / underground (u-bahn) options to get about
Train leaves every 30 mins:
From Airport it’s 09 & 39 minutes in the hour (1st train is 06:09 , last train 23:39)
To Airport from City (main train station) it’s 07 & 37 minutes past the hour, 1st train is 05:47, last train 23:07.
(Note there is 2 Euro charge more for buying tickets on the train, inspector was pretty visible when we were there both journeys so i’d Advise getting before boarding , doubtful can skip)