Boom Supersonic has raised a new $33 million Series A round, which it says is enough to build and fly its first supersonic jet, the XB-1 demonstration and testing craft, which will be a 1/3-scale prototype version of the supersonic airliner it will eventually build and sell to air fleet customers. The final Boom jet aims to be able to make the trip from NYC to London in just three hours and 15 minutes, less than half the time it takes on current transatlantic flights, at a cost of $2,500 for a one-way flight in either direction.

“This funds our first airplane, all the way through flight tests,” explained Boom founder and CEO Blake Scholl in an interview. “Now we have all the pieces we need – technology, suppliers and capital – to go out and make some history and set some speed records.”

The XB-1, or “Baby Boom” as its affectionately called at the company, will prove that Boom’s design for its final craft is sound in flight tests, paving the way for construction of its first full-size aircraft. Boom unveiled the design of the XB-1 Supersonic Demonstrator last November, and completed wind tunnel testing on a scaled down physical model earlier this year.

“We have almost all the engineering completed, and the first wing components are showing up in the office this week,” Scholl told me about their progress since wind tunnel testing. “We’re about to do structural tests, and then we’re probably about a year away from flight.”

Asked what the funding will cover specifically in terms of the demonstration plane’s development, Scholl said that the bulk will be committed to funding the existing team, and talent acquisition. The bill of materials for the plane itself is surprisingly low, given what it aims to achieve. Boom’s entire premise is that it can build supersonic jets at a price point that makes financial sense for global air carriers to purchase and operate, however, so that makes sense.

“It’s a combination of things,” Scholl said. “The build cost of the airplane itself is about $13 million. So that’s carbon fiber composites, and avionics and the hydraulics and fuel pumps and all the stuff of an airplane. The bigger cost is actually the engineering team, the development cost, so the $33 million is going towards continuing to fund the team as well as basically doubling in size this year.”

The investors contributing to the new round include 8VC, Caffeinated Capital, Palm Drive Ventures, RRE Ventures and YC’s Continuity Fund. YC President Sam Altman joins the board alongside this round, as does entrepreneur and investor Greg McAdoo. Boom’s total funding is now at $41 million, and also includes investment from Lightbank and Paul Graham.

The company will be announcing new customers (Virgin Galactic has secured the first order off the line as an early partner) later this year, Scholl says, and he suggests we’ll start to see those customers participating as strategic funding partners in future rounds.