MO SB1421

Prohibits operating unmanned aircraft (drones) within 400 vertical feet over correctional centers, mental health hospitals, open-air facilities with 500+ person capacity (lowered from 5,000), and critical infrastructure facilities

Establishes tiered penalties: infraction for basic violations; class B felony for delivering weapons or explosives; class C felony for facilitating escapes; class D felony for delivering controlled substances

Authorizes law enforcement to take mitigation measures against threatening drones, including detection, tracking, jamming, hacking, use of force, or physical capture, consistent with Fourth Amendment protections

Exempts facility employees, those with written consent, law enforcement, government officials, public utilities conducting infrastructure maintenance, railroad employees, and FAA waiver holders from restrictions

Contains emergency clause for immediate effect upon passage due to public safety concerns from weaponized drone threats