The airline won't give it to you, if that's what you're asking. Would you want them to? Think for a second. Say you spot a good looking girl on a flight, make up an excuse and the airline gives you her name. Can't see how that ends well. So, no, the airline won't help you. Social media is the only place. And FT is a good place to start. Go to the forum for the airline you were on and ask if anyone on FT was on that flight.