Distributed propulsion refers to spreading thrust across multiple smaller propulsors instead of one or two large engines, while boundary layer ingestion (BLI) specifically means placing a propulsor where it draws in air already slowed by the airframe surface, recovering some of that lost energy. Many of the 223 records in this dataset combine both ideas, for example distributing several BLI fans along a fuselage or wing. The search terms used to build this set — inlet distortion tolerance, fan pressure ratio, propulsor spacing and related terms — target the specific engineering problems that arise once you try to build either concept, not just the general idea.

The ranking covers 26 assignees, with the leading company holding 64 records against 11 for the fifth-ranked assignee and 7 for the tenth — a steep drop after the top position. That gap indicates one organisation has filed broadly across design variants of its core architecture, while most other assignees hold only a handful of records tied to specific concepts. The full ranking is rendered separately on this page; treat it as the complete list returned for this search, not a top-50 or top-100 cut.

Filing peaked in 2019 at 27 records and has since settled lower, with the 2021-to-2024 span showing a 10% decline from 10 to 9 filings — a plateau rather than a steep drop. Figures for 2025 and 2026 are still incomplete because publication typically lags actual filing by around 18 months, so those years will read low regardless of true filing activity. Treat 2024 as the most recent year with a reasonably complete count.