We have had confirmation from the EU Commission that Article 50 holders in Austria are exempt from both ETIAS and EES. As to what the airlines and border agencies are doing I cannot comment. I believe ETIAS also does not apply to Third Country Nationals who hold valid residence permits. See Article 2, section 2. – https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32018R1240&from=EN