Ampaire has closed a $19 million Series B financing round led by DiamondStream Partners, taking the hybrid-electric propulsion developer's total funding to $68 million. That figure includes approximately $25 million in non-dilutive grants and contracts supporting development and demonstration of its hybrid-electric propulsion technologies.

The round brought in strategic backing alongside financial investment. Alaska Star Ventures, the corporate venture arm of Alaska Air Group, and IAGi Ventures, the corporate venture arm of International Airlines Group, both participated, along with Pay it Forward Ventures, Massive Ventures, Techstars Ventures, Autodesk Foundation Impact Fund, Los Angeles Cleantech Incubator Impact Fund, Elemental Impact, Venn10 Capital, Gaingels, Exit Fund, Sand Hill Angels and Climate Capital. Ampaire is working with airline, cargo and government partners to prepare its hybrid-electric engines for commercial entry into service across propulsion and auxiliary power unit applications. The funding will expand engineering and operational teams, broaden commercial route flights under the FAA's eIPP programme, strengthen supplier readiness and develop early manufacturing and aftermarket capability.

Kevin Noertker, co-founder and CEO of Ampaire, says: "This financing is about turning proven hybrid-electric performance into commercialised products and scaled operations. We have consistently demonstrated the technology in flight; this capital accelerates our deployment with customers and expands our supply chain, manufacturing and operating capabilities required to reach commercial scale."

Diana Birkett Rakow, CEO of Hawaiian Airlines and executive vice president at Alaska Airlines, adds: "Hybrid-electric propulsion has the potential to improve the economics and environmental performance of regional aviation while preserving the range and flexibility operators need."

The financing will also advance Part 33 certification of Ampaire's AMP-H570, a 570kW integrated-parallel hybrid-electric power system, and the Part 23 supplemental type certification programme for the Eco Caravan, a hybrid-electric upgrade for the Cessna Grand Caravan. Ampaire operates the world's largest fleet of flying full-scale hybrid-electric aircraft and has flown more than 38,000 hybrid-electric test miles. Its Eco Caravan has demonstrated fuel burn around 54 to 57 percent lower than the legacy turboprop configuration. The company has been recognised by the World Economic Forum as a Top Innovator in Sustainable Aviation.