Militia surveillance aircraft
These more rugged, durable versions of the Boa sentry drone are piloted by militia command, and can’t be disabled by taking out some drone controller. They function as eyes in the sky for the militia forces patrolling Gotham City. They can be blinded for a bit by the Remote Hacking Device, but otherwise can’t be engaged head-on by Batman on foot. Instead, target these drones from above during their patrols along Gotham’s skyline. Glide in carefully from above, land on them, deploy Explosive Gel, then dismount and glide away. Land upon a perch somewhere and get the rigged Serpent drone in your sights to remotely detonate the gel, destroying the drone.