The Great Airship Wave (1896-97).
documentedmass_sighting_waveScandinavian "ghost rockets"
Mystery 'airship' sightings that swept the US from Sacramento (Nov 1896) through the Midwest and Texas to spring 1897 - thousands of newspaper reports of cigar-shaped craft years before practical powered flight.
Arguably the first modern mass, media-driven aerial-anomaly wave. Documented as a newspaper phenomenon; the airships as real craft are discredited (no artifact ever produced). Best-supported causes: yellow-journalism hoaxes + misidentified Venus/stars + mass suggestion. Most 1897 witnesses read the craft as a human 'secret invention', not alien.