Parses a flight plan route string into an ordered sequence of resolved route elements. Each token in the route string is classified and resolved against the configured lookup providers.
Airway tokens are expanded into waypoint sequences between entry and exit
fixes. Procedure tokens (SIDs/STARs) are expanded into waypoint sequences.
Unresolvable tokens are preserved as unresolved elements.
A stateless resolver that parses flight plan route strings into structured, resolved route elements.