Go to the " Great Circle Mapper " and use KJFK and EDDF as your choice of airport. You with see the the prefered / shortest track actually parallels the NAT very closely.
The NAT varies day to day based on winds aloft and weather patterns as well as considerations for alternate landing sites. Sometimes St. John’s and Gander are foged in, so transatlantic flights are routes north closer to Goose Bay. So maybe not the most efficient, the NAT is there for safety and passenger comfort. The Jet Stream is one of the biggest considerations when creating the daily NAT. The “push” of the Jetstream offers more benefits to the airplane / pilot then just going the shortest distance would, so there are nights (mostly) when most commercial traffic will be routed well south of the ideal track, and in fact derive an advantage in fuel and time savings by not following the shortest route.
The track a plane takes varies depending on its operational requirements as well. Where as most commercial flights can do the transatlantic crossing without stopping, many cargo and corporate flights fly at weights that require them to refuel before they continue across the Atlantic. That is why Goose Bay, Gander and St. John’s see so much business in this respect.
As for the Pacific flights, as mentioned in previous posts, the prefered route is up through Alaska and back down past Russia and into the Asian market.
So to answer the over water route question, a straight line isn’t always the shortest route around a sphere, plus you have to add this safety consideration and destination requirements. and you see most commercial aviation following the same paths requardless of equipment.
An exception to this would be small single engine planes which have to hop accross the Atlantic or Pacific routes, fuel requirements force them to plan based on where the next / closest “gas station” is.
Just for reference, the NAT is directly over my house in NL on any given day, so I see this pattern on the North Atlantic route twice daily. Day time its Europe - NA and at night its NA - Europe. So based on observation, experience and checking out NL airports on FA, this pattern is consistant.
link to “Great Circle Mapper”, KJFK to EDDF
gc.kls2.com/cgi-bin/gc?PATH=kjfk … MAP-STYLE=