![Sonex, a metal kit aircraft company that has been around since 1998, shuts down operations. [Credit: Sonex Aircraft]](https://www.flyingmag.com/wp-content/uploads/sites/2/2026/03/SHX-Full-Span-Tips-1-e1761856047.jpg)
Sonex Aircraft announced Saturday it is closing its doors immediately. The shutdown was announced in a video message by owner Mark Schaible, who attributed the decision to a “severe drop-off in sales and our bank’s unwillingness to carry forward our debts.”
Sonex Aircraft was founded in 1998 by John Monnett in Oshkosh, Wisconsin. The metal low-wing aircraft quickly became a favorite among home aircraft builders. Schaible joined the company in 2003 and became its owner in 2022.
Schaible described the conditions leading up to the decision as a “perfect storm of bank pressure, lack of sales, increasing costs, competition from our own aircraft on the used market, and cash flow realities are now not allowing us to continue our work.”
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Schaible’s voice shook as he explained how they had fought “tooth and nail” to make Sonex successful.
“It’s incredibly painful for me to bring this news to you today—my wife and I will be filing a personal bankruptcy,” he said. “In addition to the bankruptcy of the business, we are now unemployed and struggling.”
He noted that this was the second time Sonex had broken his heart—the first coming in June 2015 when Jeremy Monnett, son of Sonex founder John Monnett, and assembly mechanic Mike Clark were killed in the crash of a Sonex SA at Wittman Regional Aircraft (KOSH).
Schaible didn’t disclose how much money it would take to save the company. But he did state an 11th-hour investment or purchase to allow the company to continue is unlikely, as this is more severe than a reorganization of debts.
“Both John Monnett and myself are very interested in finding someone willing to step up and support the worldwide Sonex fleet in some capacity, and [that] hopefully includes completion of the work required to ship Sonex high-wing kits,” he said.
He said they also are speaking with key vendors and contacts, hopeful that they can find a way to make this work with whomever takes over production. He offered his most sincere apologies to those negatively affected by this situation, including vendors, staff, and customers.
Schaible asked people to be respectful to the staff who are now without jobs and said he realized there will be people who are angry.
“Our only consolation is knowing that with their talents and dedication they will earn a lot more money elsewhere than they have with Sonex,” he said.
Schaible began his journey with the Experimental Aircraft Association (EAA) at age 14 when he joined EAA chapter 44 in Brockport, New York. His father would drive him to the monthly meetings.
“This is not how I wanted my EAA story to end,” he said.
As of March 2026, approximately 700 Sonex aircraft have been built, and more than 2,100 projects are in the works, according to company records.
