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Overair (Karem) Butterfly

Overair Butterfly eVTOL passenger aircraft flying over a city landscape


Overair, Inc.
Santa Ana, California, USA

Overair, Inc. is a spin-off from Karem Aircraft and is located in Santa Ana, California, USA. Overair became its own independent company in 2019 and will be making the production prototype for their electric vertical takeoff and landing (eVTOL) aircraft named Butterfly.

Karem Aircraft was founded by Abe Karem in 2004 in California, USA. Ben Tigner was the President and CEO of Karem Aircraft and as of January 2020, is now the President and CEO of Overair. Uber Elevate announced on May 8, 2018 that it was adding Karem Aircraft (now Overair) as one of its aircraft partners to design an eVTOL aircraft for Uber's Elevate ecosystem. In December 2020, Uber sold Uber Elevate to Joby Aviation.

In July 2019, it was reported that Korean industrial conglomerate Hanwha Systems, pending regulatory approval, will invest $25M in a subsidiary of Karem Aircraft to develop the Butterfly eVTOL aircraft for Uber Elevate's mission. On Jan. 15, 2020, it was announced that Hanwha Systems was approved for the $25M dollar investment for Karem's spin-off company, Overair. Hanwha Systems now owns 30% of Overair, Inc.

Revealed to the public in August 2021, the new Overair's eVTOL Butterfly production aircraft is a sleek and elegantly designed quad-tiltrotor aircraft. The Butterfly has one pilot and carries five passengers with their luggage. The aircraft's estimated cruise speed is 200 mph (322 km/h), a range of 100 miles (161 km) and with a payload 1,100 lb (499 kg). While the new design is mostly similar to its previous configuration, the size of the rear props has been increased to allow the Butterfly to land if one prop is damaged.

The Overair Butterfly uses the company's patented Optimum Speed Tiltrotor (OSTR) technology which has a far higher system performance than typical tiltrotors (according to Overair), through integrated improvements in multiple technologies. Optimum Speed Tiltrotor technology has the following characteristics of variable-speed tilting electric rotors (individual blade control), uniquely designed blades, lightweight composite blades, high efficiency aerodynamics and more. The Butterfly configuration solves the trade-off between hover and cruise efficiency, creating an optimal vehicle configuration for advanced air mobility (AAM).

The larger slow turning rotor propellers provide more efficient lift, safer flight, quieter acoustics and draw less power from batteries than aircraft with smaller propellers. This design feature provides an immediate economic impact by making the Butterfly less costly to fly. The most recent information from Overair as of August 2021 includes claims that the Butterfly will be the quietest eVTOL in the industry when they launch. Two statements were given to support this claim, the noise produced by the aircraft is low and the frequency of the noise is one which humans are less likely to register. If this is the case, it stands to have a major advantage over competitors in both public acceptance and passenger comfort.

According to Overair's Ben Tigner, using large slow tiltrotors makes the Butterfly a more efficient and faster aircraft on less power. While efficiency sounds academic, efficiency translates into real economic and operational advantages. For example, the Butterfly can fly multiple advanced air mobility missions on a single battery charge with a lot of reserve power and it doesn't need to rely on any exotic power system. All one needs is batteries. Efficiency also means the aircraft can fly faster, for example, the aircraft will increase it's cruise speed from 150 to 200 mph (240 to 322 km/h), allowing a shorter time period between trips.

Electric motors are quieter and provide a higher margin of safety. High efficiency allows the aircraft to perform well with unexpected wind gusts or unexpected traffic, the aircraft can easily maneuver through these situations where turbine jets or planes might have more trouble.

On June 14, 2022, Overair announced they received $145 million in funding from Hanwha Systems and Hanwha Aerospace, headquartered in Changwon, South Korea. With this new investment, Overair plans to use this money to fly its eVTOL prototype aircraft in the second half of 2023 and to help commercialize their eVTOL  passenger aircraft. In addition to their investment, Hanwha will also provide electric motors and battery packs for Overair's prototypes.

Overair aims to have the Butterfly FAA certified by 2025 and launch operations in 2026 in the United States and Korea for use in advanced air mobility operations.

Butterfly eVTOL in forward flight

Butterfly eVTOL in forward flight

Butterfly eVTOL hover mode

Butterfly eVTOL hover mode

Butterfly eVTOL in forward flight

Butterfly eVTOL in forward flight


  • Aircraft type: eVTOL passenger aircraft
  • Pilot: 1 pilot
  • Passengers: 5 passengers with luggage
  • Speed: 200 mph (322 km/h)
  • Range: 100 miles (161 km)
  • Payload: 1,100 lb (499 kg)
  • Propellers: 4 propellers. A quad tiltrotor with Optimum Speed Tiltrotor (OSTR) technology. A large rotor, slow turning propeller.
  • Electric Motors: 4 electric motors
  • Power source: Batteries
  • Wing: 1 high wing
  • Tail: 1 V tail
  • Landing gear: Retractable landing gear
  • Safety features: Distributed Electric Propulsion (DEP), provides safety through redundancy for its passengers and/or cargo. DEP means having multiple propellers (or ducted fans) and motors on the aircraft so if one or more propellers (ducted fans) or motors fail, the other working propellers (or ducted fans) and motors can safely land the aircraft. There are also redundancies in the sub-systems of the aircraft.

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