Otto has frozen the natural-laminar-flow aerodynamic design of the Phantom 3500.
U.S. startup Otto Aerospace has moved into detail design of the Phantom 3500 business aircraft, advancing its plans to exploit drag-reducing laminar flow technology to develop a light jet with the cabin size and performance of a super midsize jet.
Otto announced May 13 it had frozen the aerodynamic design and major interfaces and begun detail design after completing the preliminary design review (PDR) at the end of February. The startup plans to fly the first Phantom 3500 flight test vehicle, FTV1, late in 2027, according to Otto CEO and President Scott Drennan.
The two-day design review for the Phantom 3500, known internally as the 800 Project, was conducted at Otto’s planned headquarters and production facility at Cecil Airport in Jacksonville, Florida. The Fort Worth, Texas-based startup secured an almost $500 million incentive package from Florida in July 2025 to locate its manufacturing facility in Jacksonville.
The Phantom 3500 features natural laminar flow (NLF) aerodynamics that were flight tested on the Celera 500L, a full-scale piloted technology demonstrator that flew in 2018 and achieved 59% lower drag compared to conventional aircraft of similar size, Otto says.
Through careful shaping of the fuselage and wing, NLF technology aims to minimize drag by maintaining smooth airflow over as much of the airframe as possible to avoiding increased skin-friction drag caused by turbulent flow.
On the Phantom 3500, which features a slotted NLF wing that Otto says maintains laminar flow over 85-90% of its upper and lower surfaces compared with less than 20% for a conventional wing, the technology is expected to reduce fuel burn by more than 60%.
Otto formally launched the $19.5 million Phantom 3500 last September with a 300-aircraft order from fractional-ownership operator Flexjet. From the concept aircraft shown then to the current PDR configuration, Otto says it has made several refinements to the aerodynamic lines using its laminar flow analytical toolset and has continued to mature the aircraft systems and structures.
“The aircraft configuration remains fundamentally the same, with range, speed, cabin size and experience, fuel burn, and maximum takeoff weight unchanged,” the company said.
With a maximum takeoff weight of 19,000 lb., Otto plans to certify the Phantom 3500 under FAA Part 23 regulations, but offer a 3,500 nm-range, 51,000 ft.-ceiling aircraft with standup cabin that competes with more expensive super-midsize business jets certified under Part 25. Operating costs are projected to be 50% lower than for a super midsize jet.
“The Phantom 3500 has crossed the threshold from a promising concept to an aircraft we are preparing to build and fly,” Drennan said. The planned flight-test program will support efforts to demonstrate the producibility and performance of the laminar-flow technology.
Otto aims to certify the Phantom 3500 in 2030. To achieve the smooth surface finish critical to achieving laminar flow, Otto plans to use an out-of-autoclave resin transfer molding process for manufacturing composites. Leonardo is to make the fuselage, Belgian company Sonaca the wing, and Williams is to supply the FJ44-4QPM engines.
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