In 2001 I got a great deal flying to NYC as a courier. I had to hang around a special desk landside at LHR until quite close to the flight, then pick up some documents and hand them over again on arrival. Return was task-free.

Suddenly remembered about it and thought I'd not seen it mentioned on FT. Do they still exist? It was only certain routes, and Y of course, but IIRC I paid about £250 return. They only needed one per flight so it was great for me as I was travelling to meet a friend. Downside was no duty free time but the savings certainly helped my cash strapped younger self.