Abstract: The present invention comprises a novel method for passive wide-area interdiction of small remotely controlled or fully autonomous airborne devices, commonly referred to as drones, whether singular vehicles or in swarms, by deploying a low-cost fouling material into the desired protection zone. The deployed fouling material being light-weight, so as to float through and widely disperse within the airspace over the protected zone, then so designed to physically ensnare or attach itself in a manner to degrade the flying capability or other mission capabilities of the unwanted drones passing through or loitering within the protected airspace. One example, but not the only example, of such embodiment might be dispersal of very fine synthetic spider-silk threads having the characteristic of high-strength combined with kilometer-lengths and a relatively short active state life span, after which naturally and relatively quickly dissolving with any remaining residue being absorbed into the environment.