Every critical path is defined by three things:
Airline
Airport
Aircraft type
If a flight matches an airline and airport that have a configured critical path, but no critical path exists for its aircraft type, AGOA applies the default critical path for that airline and airport.
This lets several aircraft types that follow the same turnaround process share one configuration, so you don't have to create and maintain a separate critical path for each aircraft type.
A default critical path is identified by a checkmark:
