The ST-4 Aztek features a strut-braced high-wing, a two-seats-in-side-by-side configuration enclosed cockpit, fixed tricycle landing gear with wheel pants, a small tailskid and a single engine in tractor configuration.

The wings are supported by V-struts with jury struts and the empennage is cable-braced.

The engine is mounted high above the cockpit on the front end of the aluminum tube that acts as the tailboom.

[1] The manufacturer estimated the construction time from the supplied kit as 80 hours.

[1] By 1998 the company reported that 26 kits had been sold, and that 15 aircraft were completed and flying.