The organization behind the futuristic NEOM tourism-driven enclave close to the Red Sea, Saudi Arabia’s Neom Investment Fund, is contributing an undisclosed sum to Boom Supersonic, a U.S. startup that aims to commercialize a supersonic passenger jet.

After the completion of its most recent funding round, the size of which the company declined to disclose, Boom said that it has raised more than $700 million to date.

Up to $9 billion will be needed for further development in order to bring Boom’s Overture aircraft into commercial service by 2030, CEO and co-founder Blake Scholl revealed to The Messenger. He refused to say how much the business is worth or whether a fresh round of funding has been started. “Developing new aircraft is not cheap,” he remarked.

Using sustainable aviation fuel (SAF), the four-engine Overture aircraft is intended to transport up to 80 passengers at Mach 1.7, mainly over the Atlantic. Flights across the Pacific will need to stop for refueling.

Although the Overture will travel more slowly than the Concorde, which made its final flight in 2003, Scholl claims that it is built to run more smoothly, resulting in ticket prices that are on par with current business class fares.

Boom intends to fly its XB-1 demonstration aircraft for the first time before year-end, and this investment comes just weeks before that date. Driven by three GE Aerospace J85 engines, the demonstrator is a scaled-down platform to test technologies intended for the larger Overture.

Ahead of the first flight test, Boom has been conducting high-speed ground testing on the aircraft in Mojave, California, and has recently reached a top speed of 94 knots (108 mph). Boom has not yet revealed the date of that flight, but according to Scholl, it is one of many benchmarks that the XB-1 program needs to clear before reaching supersonic speed in 2024.