A Covid-19 vaccine is unlikely to be a quick fix for the ailing travel industry, which will still take years to recover to pre-pandemic levels, according to Booking.com.“We believe that a vaccine and/or proven treatment is critical for people to feel safe to travel again, and even then, it will be years – not quarters – before travel returns to 2019 pre-pandemic levels,” said Angel Llull Mancas, vice president and managing director, Asia-Pacific, at the online travel service provider.If and…