The Titile

You have to live in Europe to know what it means: it's about the pigeon sport. In the film you can see that pigeons are transferred to France and there they let them free. At that moment the race starts and the pigeons have to fly back home as fast as they can. The first pigeon that arrives home wins the race.
Now, "the conveyors are waiting" (les convoyeurs attendent)comes from the very beginning of the film, when you can hear a radio news bulletin about the weather conditions at the places where the pigeons are set free. When the weather is not good enough to let the pigeons fly back home, they say "les convoyeurs attendent" (= the conveyors are waiting to let the pigeons go).
But there is a much better film with the same main character (the vile man) which is much funnier and better: "Man bites dog" ("C'est arrivé près de chez vous"). THAT is a good film!