I actually can't find any evidence that there ever existed a direct Anchorage-Belize trip. The parent comment implies that the company merely offered routes that extended to these destinations, but not necessarily as a single trip.
That is indeed what I was trying to imply. Although, as someone who grew up on the West Coast, I have to say that similarity in distance is still a bit surprising to me.
Across Eurasia. There might be some cultural/imagination thing going on. I have driven from British Columbia to Tijuana. I cannot even imagine how that would be across Eurasia.
Most of Anchorage to Belize would be within two or three countries: USA, Canada and Mexico, and two main official languages English and Spanish. (Obviously numerous indigenous minority languages.) London to Calcutta would have been much more diverse, but even within the Indian leg you would encountered more languages...
Anchorage to Belize: 5777 miles
London to Kolkata: 5695 miles