Boom Technology has made a significant step forward in its quest to build a new generation of supersonic passenger planes, as it recently announced that it has quadrupled its working capital. Through Series A funding involving 8VC, Caffeinated Capital, Palm Drive Ventures, RRE Ventures, Y Combinator's Continuity Fund, and several angel investors, the company has raised an additional US$33 million, giving it a total capital of US$41 million.

Comparing its efforts to develop a new supersonic commercial airplane to last century's transition from transoceanic clippers to jets, Boom plans to use modern engines and materials to develop a supersonic passenger jet that can cruise at Mach 2.2 (1,675 mph, 2,700 km/h), with prices starting at $5,000 for a return ticket between London and New York.

As part of this effort, the company is already working on a one-third scale prototype called the XB-1, which will act as a technology demonstrator and is scheduled to fly later this year. Boom CEO and founder Blake Scholl says that the new capital will allow the construction and testing of the prototype to go forward to completion and "set a new speed record for civil aircraft."

In addition to the increase in capital, Y Combinator President Sam Altman and investor/entrepreneur Greg McAdoo are joining Boom's board of directors.

The video below outlines Boom's philosophy of supersonic flight.