Singapore Airlines Cargo aircraft landing, location unknown, 30/07/2015. https://www.rawpixel.com/image/6111589/photo-image-public-domain-technology-skyFree Image from public domain licensea plane in the sky. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3289935/free-photo-image-sky-blue-pastel-skies-adventureFree Image from public domain licenseStar Alliance & Air Asia airlines, Singapore Changi airport, 8/06/2016. https://www.rawpixel.com/image/6113002/photo-image-public-domain-technology-skyFree Image from public domain license