Density altitude is best described as:

Why →Density altitude is pressure altitude corrected for non-standard temperature. It represents the altitude in the International Standard Atmosphere (ISA) that corresponds to the actual air density. High density altitude means thin air. The aircraft "performs as if" at a higher altitude than its actual elevation.

The trap →Pressure altitude (altimeter at 29.92) is the baseline before temperature correction. Actual MSL height doesn't account for air density at all. Density altitude is the performance-relevant number, not pressure altitude.

Field note →Hot + high + humid = high density altitude = degraded performance. On a hot summer day at a 5,000-foot airport, density altitude could be 8,000 feet, meaning the drone performs as if flying at 8,000 feet even though it's at 5,000.