Nasa will fly the X-59 in conjunction with community surveys to assess what people think when a supersonic boom is bent by the planes stretched nose and hushed up.

"We want to figure out what level of boom is acceptable to people on a regular basis," says Coen, who reckons his machine will sound "like a car door being closed across the street" when it flies past Mach 1, around 660mph at airline cruising altitude.

With its cockpit and ejector seat taken from a T-38 training jet, its landing gear from an F-16 fighter and engine courtesy of the F-18 this jigsaw of an aircraft was assembled by Lockheed Martin for Nasa.

A camera feeding a screen in front of the pilot relies on instantaneous computer processing to get round the lack of forward vision.

It first flew in 2025, has gone supersonic and will break the sound barrier over chosen US towns in 2027.

But is there still a place for X-plane projects in a world where relatively cheap drones are being rapidly developed - not least in Ukraine's war against Russia.

Even Nasa considered an uncrewed X-59. But drones are not always a cheaper option.

Removing the pilot would have added the cost and complication of certifying a robot jet to fly fast over urban areas.

Plus the X-59 had to be big enough to resemble an airliner punching through the sound barrier, which in turn allowed space for a cockpit.

Nasa is no stranger to drone X-planes. The X-48, a scaled down model of an airliner that blends wing and fuselage to create a single lifting body, flew in 2007.

Small was beautiful for the tiny X-48 with its 20ft wingspan as this kept the programme within budget.

"It's likely that future X-planes will be uncrewed," says Coen, before adding the vital caveats "unless the technology we're researching relates to piloting or if crewing it is more cost-effective".