A transponder is crucial for identifying aircraft. There are 3 types of transponders: Mode A, Mode C, and Mode S. Significant squawk codes to remember: 7700, 7600, 7500, 7000/1200, 2000.

From plastic bags reported as drone incidents through to airports closed with no evidence of drones being involved, it’s clear that drone ... safety to fit an ADS-B transponder to their aircraft ...