Were faster aircraft operating on this route at some point? Nowadays Icelandair says 5hr15min BOS->KEF and 5hr50min on the way back.
The airline would rather the trip take zero hours because crew costs hourly and they want to turn that seat around and sell it again but they have to balance that against fuel costs.
The airline would rather the trip take zero hours because crew costs hourly and they want to turn that seat around and sell it again but they have to balance that against fuel costs.