Gst for air ticketing agents working under airlines or online tracvel portal

I run a proprietorship firm which is a B2B sales agent working under Goair, indigo etc and also under travel portals like yatra, via. I ​ha​ve not yet received Provisional ID for GST I get commission from air ticket sales and TDS is deducted. i.e I book tickets on behalf of Airlines and travel portals and sell them. Now since th GST is in force , Do I have to charge 5% GST on economy class from customer even if 5% GST is already charged by the Airline in the total airfare ? do i need to raise separate GST invoice for customers?