One assignee leads clearly with 392 of the 1,589 records in scope, well ahead of the fifth-ranked holder at 53. The top five assignees combined hold 972 records, or 61.2% of all records in scope, meaning a small group has shaped the core claim space in glide slope capture, autoflare and related functions. Beyond the top ten, holdings drop off quickly, with a long tail of single- or few-filing entrants making up the rest of the ranked field.

Filing volume fell from a peak of 90 in 2022 to 38 in 2024, a decline of 55% documented over that three-year span. However, patent publication typically lags the actual filing date by around 18 months, so 2025 and 2026 figures in any dataset are still incomplete and should not be read as proof the field has gone quiet. The more reliable read is that activity cooled from an unusually active 2021-2022 period rather than that innovation has stopped.

Two IPC subclasses dominate: G05D, covering control of non-electric variables, appears in 37.1% of the 1,589 records, and G08G, traffic control systems, in 32.4%. Aircraft equipment (B64D) and navigation and gyroscope systems (G01C) both feature in roughly a quarter of records. Because a single patent can carry several classification codes, these percentages overlap rather than sum to 100%, and the pattern shows the field is claimed mainly at the control-logic and traffic-management level rather than at the airframe or propulsion-hardware level.

US3994455A, granted to The Boeing Company in 1976, claims an automatic approach pitch axis control system using an exponential control law for glide slope capture, with an altitude-rate command coupler that handles the capture manoeuvre from above or below the beam. It is a foundational reference for glide slope capture logic that predates almost all of the 1,589 records in the current dataset. While the specific patent term has long since expired, its approach — decreasing beam-error-driven capture — remains a conceptual baseline that later, still-active filings build on or design around.

The technology composition data shows gas-turbine integration (F02C) present in only 3.3% of records, well below the 25-37% range of the core control, traffic and navigation classes, suggesting autothrottle-to-engine integration claims are comparatively under-filed relative to control logic alone. Sub-areas tied to newer operating conditions — crosswind-adapted rollout guidance, GNSS-degraded runway alignment, and flare-law adaptation for variable loading — are not separately broken out in the classification data but are consistent with functions named in the search scope that see little concentrated ownership among the top holders. A freedom-to-operate check against the leading assignees' active families is the appropriate next step before relying on this as a filing strategy.