International Institute for Strategic Studies (IISS) — London-based defense and security think tank. Published a July 2, 2026 report documenting hundreds of Russian drone incursions across nato airspace (Aug 2024–Feb 2026), including repeated surveillance of nuclear-mission bases ramstein-air-base and volkel-air-base. The report attributes the campaign to a Russia-linked “shadow fleet” of North Sea/Baltic vessels and calls for clearer legal authority to counter deniable, below-threshold drone incursions.