A Fly was a type of light horse-drawn carriage [however "fly" as a noun has well over a hundred different uses in English]. That fact, and the word "stable" leads one to suspect he was a stablehand or coach driver. One would need to know the full details in order to examine the entry better.
Your other post for Motor Man needs date clarification. He would not have been a driver of any kind before the early 1900's at best. However he may have been an attendant upon a motor or a mechanic or the "driver" of a stationary engine. when was this, where did he live?
We'll help you more easily with queries if you remember we need to know Who? When? Where?
Hack
