It was only 1. If you look closely, you'll see that all "4" arrived at the same time. That is known as a codeshare. Only one physical plane arrived, but it was operating on behalf of four airlines. London City doesn't have Portuguese arrivals at all. I haven't checked the others. Edit: I'll save you the bother of looking closely. I would guess thats American Airlines, someone, British Airways and Cathay Pacific. The three are involved in a strategic alliance known as OneWorld. How do I know all this? My parents have worked at Qantas since 1983.