Completely documented proof of performance (extract from flight log, license, etc.).
Completed training with Matura/Abitur or diploma HF or general university entrance qualification or technical college entrance qualification.
Very good language skills in German (at least language level B2 must be proven, if German is not your native/everyday language) and good conversational skills in English (at least ICAO level 4).
General willingness to be vaccinated with vaccines approved in Switzerland (including COVID-19, yellow fever, etc.)