When it was over there were SEVERAL airlines flying the Pacific. In 1961 there were so few airlines flying the Pacific, and so few flights, that it was common to take hops across the Atlantic and Indian Oceans to East Asian ports to then access Japan and Korea.
The trans-Pacific is a tough route to monitor Air Traffic wise until lately, because the long range radio contacts are so feeble and full of static. The radio operators who worked that are said to have had really good ears and a gift for it.