The number of passengers flying to Hong Kong with Cathay Pacific Airways plunged 38 per cent in August as the often violent anti-government protests scared away foreign travellers during one of the busiest months for travel.And there would be no let up in the weakening business environment, the city’s largest airline group warned on Wednesday, saying September would also be challenging.Demand for business class travel, which supports far more of Cathay Pacific’s revenue compared with economy, …