Whisper Aero sells $46.3M in equity without naming the round

Why it matters

Whisper Aero's largest SEC-disclosed equity sale gives Moore and Villa room to move from acoustic proof points into aircraft integration and production. The filing also shows why round labels require scrutiny: Whisper Aero's 2023 SEC total exceeded the Series A it announced.

Mark Moore and Ian Villa's Whisper Aero sold $46.3 million of equity to 16 investors, according to an SEC Form D filed on September 17th. The fully sold offering is the largest Whisper Aero has reported in a single SEC notice and puts new capital behind the founders' push to move quiet electric propulsion from demonstrations into crewed aircraft and customer platforms.

The filing gives September 2nd as the first sale date and reports an exact offering amount of $46,317,349, with the same amount sold and $0 remaining. Moore signed the filing as chief executive. Whisper Aero has not attached a round name to the financing, and the filing does not identify its lead investor, valuation, share price or the 16 buyers.

Moore has spent most of his career pursuing distributed electric propulsion. During more than 30 years at NASA, he led projects including Puffin, GL-10, LEAPTech and X-57 before co-founding Uber Elevate and serving as its engineering director. Villa, who studied aeronautics and astronautics at Stanford, worked in Northrop Grumman's advanced design group before joining Moore at Uber Elevate.

The pair founded Whisper Aero in Crossville, Tennessee, after concluding that noise would constrain electric aviation even if batteries and motors improved. Whisper Aero grew out of a 20-acre resort converted into a private laboratory in 2020, where the early team lived and worked while developing its first propulsors.

A $46.3M filing with few labels

The new financing is larger than the $32 million Series A that Whisper Aero announced in April 2023. That round was led by a syndicate of Menlo Ventures, EVE Atlas, Capricorn's Technology Impact Fund and Connor Capital, with participation from Kindred Ventures, Abstract Ventures, Moving Capital, AeroX Ventures, Cosmos Ventures, Linse Capital and Launch Tennessee.

Whisper Aero's earlier SEC notice complicates a simple comparison between announced rounds and regulatory filings. A July 2023 Form D reported $41.4 million sold to 38 investors, even though Whisper Aero described its Series A as $32 million. The filing did not explain the difference. The two SEC notices together report roughly $87.7 million of equity sold, while Whisper Aero's named rounds use different totals.

That mismatch is also a reason to avoid assigning the new financing a Series B label before Whisper Aero does. Form D records the exempt securities sale. It does not define how Whisper Aero or its investors will present the transaction.

Shawn Carolan, a Menlo Ventures partner, appears in the new filing as a Whisper Aero director, alongside EVE Atlas founder Thiago Olson. Carolan's board role reflects Menlo's continuing relationship with Whisper Aero, though the filing does not establish that Menlo participated in the new offering.

Moore's noise thesis reaches crewed flight

The capital arrived shortly after Whisper Aero produced its strongest public proof point for Moore's central thesis. In August, Whisper Aero completed three crewed flights using two eQ250 electric ducted fans mounted on a modified Aeriane Swift 3 glider at its Crossville test facility. The campaign accumulated more than 130 minutes in the air, Aircraft Investor reported.

Whisper Aero reported 52 dB(A) from the aircraft at an altitude of 100 feet against ambient noise of 34 dB(A). Those acoustic measurements remain company-reported, although the flights moved the eQ250 beyond laboratory testing and onto a piloted aircraft operating under an FAA special airworthiness certificate.

The eQ250 is Whisper Aero's largest listed production-oriented propulsor. Whisper Aero rates it at more than 70 pounds of thrust and targets Group 3-plus drones and fixed-wing aircraft. Whisper Aero also markets the smaller eQ120 and eQ160, and claims its architecture can scale from 5 to 500 pounds of thrust. Its comparisons of 20 decibels less noise and 20% greater efficiency are company claims.

The founders are pursuing a supplier model across several markets rather than staking Whisper Aero on a single aircraft. Whisper Aero is developing propulsion for drones, fixed-wing aircraft, defense logistics systems and ground equipment. It has also published concepts for a nine-passenger Whisper Jet and a 100-seat Whisper Jetliner, long-range designs that demonstrate where Moore believes distributed electric fans can eventually lead rather than aircraft nearing certification.

Capital for integration and production

Whisper Aero's immediate work is more concrete. The August flight campaign followed more than 1,000 hours of propulsion life testing, according to Villa, and Whisper Aero has said it is preparing further acoustic testing with the U.S. government. Whisper Aero is also developing Collaborative Logistics Aircraft for defense missions with support from U.S. Air Force STRATFI and Operational Energy Capabilities Improvement Fund programs.

Whisper Aero has built infrastructure around that work in Tennessee. It operates an 8,000-square-foot flight-test center at Crossville Memorial Airport, funded in part by a $1.2 million appropriation from the Tennessee General Assembly. Whisper Aero also completed AS9100D and ISO9001 quality-management certification in 2025. The certifications give the company a baseline for aerospace and defense supply work, but they do not establish aircraft certification, production at scale or customer deployment.

The $46.3 million sale gives Moore and Villa substantially more room to finance aircraft integrations, testing and manufacturing as those programs move forward. It does not settle the commercial questions that follow a successful flight test. Whisper Aero still has to turn acoustic performance into repeatable production, certified integrations and contracts large enough to support an aerospace supplier.

Moore has been working on distributed electric propulsion since long before electric aviation became a venture category. The new financing backs the same career-long thesis at a more expensive stage: getting the fans off test stands, onto aircraft and into production.