The Sonex is the brainchild of John Monnett, a legendary figure in the experimental aviation community. Designed in the late 1990s at Wittman Regional Airport in Oshkosh, Wisconsin — the spiritual home of homebuilt aviation and host to the world's largest airshow, EAA AirVenture — the Sonex was born from a simple idea: anyone should be able to afford to fly.
The design is pure elegance through simplicity. An all-metal airframe of 6061-T6 aluminum, assembled with pulled rivets that any motivated builder can learn to set. No composites, no wood, no fabric — just honest sheet metal that can be repaired in any hangar with basic tools. The distinctive Y-tail isn't just visually striking; it reduces drag and weight compared to a conventional empennage.
The heart of most Sonex aircraft is the AeroVee 2.1 — Monnett's conversion of the venerable Volkswagen Type 1 flat-four engine. At 2,180cc and 80 horsepower, this air-cooled powerplant costs a fraction of a certified Lycoming or Continental, yet reliably propels the Sonex at 130 mph cruise. It's the same fundamental engine architecture that powered millions of Beetles — reimagined for the sky.
With a build time of 800–1,200 hours and a total cost under $40,000, the Sonex represents the most accessible path to aircraft ownership. And despite its modest price tag, it's rated for +6g / −3g — meaning loops, rolls, and hammerheads are all on the menu. Few aircraft at any price can match that combination of affordability, performance, and aerobatic capability.