Pilot Makes Emergency Landing After Venomous Cobra Found Under Seat

South African pilot discovers Cape cobra hiding under his seat mid-flight, prompting immediate emergency landing.
Neither pilot nor passengers harmed; snake eludes search and capture, believed still on loose in plane.
Theory emerges that cobra stowed away before flight and remained hidden until pilot's startling discovery.
Despite two-day search, cobra's current whereabouts unknown; plane grounded indefinitely.