The Advanced Research Projects Agency-Energy (ARPA-E) is issuing a Request for Information (RFI) regarding the integration of electric powertrains into existing aircraft, specifically focusing on technologies developed under the ASCEND initiative. This RFI aims to gather insights on the feasibility and impact of retrofitting aircraft with electric propulsion systems and advancing airport electrification, while addressing challenges such as powertrain efficiency and structural integration. The initiative is part of a broader effort to promote sustainable aviation through innovative electrification strategies, and contributions are encouraged from various stakeholders, including aircraft manufacturers and research institutions. Responses to this RFI should be submitted in PDF format by 5:00 p.m. Eastern Time on May 31, 2024, to ARPA-E-RFI@hq.doe.gov, with further details available at https://arpa-e-foa.energy.gov.