Who is Bushplane Pilot from Brian's Winter and what is their importance?

David Smallhorn is resupplied every six weeks by a bushplane that brings perishable food and other supplies. When the plane comes three weeks after Brian finds David and his family, he is given his chance to return to civilization. The bush pilot rushes Brian to leave so that he can avoid approaching weather. Brian hesitates, but finally he returns to civilization with the bush pilot.