What are the circumstances in which Billy meets the gypsies?

The horse is lying down as it has been since soon after the stabbing. Billy tries to give the animal water but the horse can't drink without rising up and Billy gives up. Soon after, Billy hears someone approaching and he goes to the road to meet them. The travelers are gypsies and are dressed in gaudy costumes. They have oxen pulling a cart and in the cart is an airplane. They ask about the horse and Billy tells them what happened. One of the men asks if the horse is for sale, and Billy knows that the animal will live. The men heat water with some leaves in it and use a funnel and hose to pour the contents into the horse.