Thiruvananthapuram: Vistara Airlines, a joint venture of Tata Sons Private Limited and Singapore Airlines Limited (SIA), will be launching its second daily flight service to Mumbai from the state capital on September 1, the Thiruvananthapuram International Airport Ltd (TIAL) said on Thursday. The new flight service would depart from Thiruvananthapuram at 8.30 AM and reach Mumbai at 10.45 AM, TIAL said in a statement.