One who flees or attempts to escape; a person involved in fleeing or taking flight.
From flight plus the agent noun suffix -er (one who flies/flees), creating a noun for someone characterized by the action of flight or fleeing, following standard English word-formation patterns.
Flighter is a word that bridges literal flight (flying away) and metaphorical flight (escaping)—it reminds us how fundamental fleeing is to survival, appearing in everything from wildlife biology to descriptions of refugees and runaways.
Complete word intelligence in one call. Free tier — 50 lookups/day.