Vertical Aerospace has entered the fourth and final flight test phase for its electric vehicle takeoff and landing (eVTOL) prototype aircraft, having received a ‘Permit to Fly’ from the UK Civil Aviation Authority (CAA).
On November 13, 2025, Vertical announced that, earlier in the day, test pilot Paul Stone had flown the first flight of the transition stage, a process that will see the VX4 prototype shift between hover and wingborne flight.
Vertical Aerospace completed prototype flight test phases 1, 2 and 3 earlier in the year, which included flying in open air space for the first time.
Before commencing the first transition phase flight, the Vertical team undertook extensive simulation, ground, and flight testing in collaboration with the UK CAA, verifying all 200 minimum safe aircraft requirements.
According to Vertical, more than 20,000 pages of safety and technical information were updated and submitted to the CAA during the process of gaining the Permit to Fly.
As we enter into Phase 4, we're sharing a detailed breakdown of our piloted transition test phase, showing the different profiles from start to finish.#eVTOL #AviationNews #verticalaerospace #FutureOfFlight pic.twitter.com/FjxRwWphDG
— Vertical Aerospace (@VerticalAero) November 13, 2025
Stuart Simpson, CEO of Vertical Aerospace, said: “Receiving our Permit to Fly and starting Phase 4 marks a defining moment for Vertical Aerospace. Our team has spent months verifying every core system under close regulatory oversight, reflecting our unique and robust approach to certification.”
He added: “This step is a critical demonstration of the VX4’s unique tiltrotor capability and real-world capability and is a major technical and certification unlock.”
Vertical’s piloted flight test program explainer:
Phase 1: Tethered: the VX4 prototype will perform a stabilized hover while loosely tethered to the ground (completed on September 12, 2024).
Phase 2: Thrustborne: the VX4 prototype will take off and land vertically and conduct low speed flight maneuvers with lift generated by the propellers (completed February 4, 2025).
Phase 3: Wingborne: the VX4 prototype will take off, fly and land like a conventional aircraft, with lift generated by the wing (completed September 5, 2025).
Phase 4: Transition: The VX4 prototype will transition between thrustborne and wingborne flight, and vice versa (full transition expected before end of 2025).
The VX4 is designed to carry a pilot and four passengers. On May 12, 2025, Vertical unveiled plans to build a hybrid-electric version of VX4 that will have a range of up to 1,000 miles (1,600km) with a maximum payload of 1,100 kilograms (2,424 lbs).