I have an American passport and I know that I can enter Austria visa-free for 90 days. I want to do an internship/apprenticeship at an Austrian company. It will be unpaid work. Will I need a visa or a work permit or something of that sort? Also, if I instead decide to do a summer school at a local college, would I still need a visa? My dad lives in Austria and works there and can support me, and I am legally eligible for the Red White Red card Plus which entitles me to live there and work there, but due to the amount of time that it takes to apply for one, I would like to avoid this option.