Beekeepers have known this for a long time. Treeline, fencelines, streams, etc are great places for swarm traps. Beelining also makes this pattern somewhat apparent.
It seems natural that straight lines across a landscape would be useful markers. I wonder to what degree bees use non-linear landmarks, if at all. In an environment with many straight lines, like an agricultural field with row crops, irrigation channels, fences, and one wavy creek bed, would the irregular feature be a helpful marker?
Pilots still do this. It’s called visual way finding. It’s mostly practiced as a skill in case the GPS fails these days.
I've only heard it referred to as pilotage, but yes it's a skill you'll learn in the first 2-3 lessons of flight training.
And how do they navigate when it is misty?
At least for honeybees, in general they don't.
Source: my own beehives.
It would have to be extremely misty to interfere with bees on the level they operate at. They fly so close to the ground their landmarks are probably less than a meter apart. It almost never gets misty enough to not be able to see that far. In that case I would bet bees just stay home at the hive.
At least for honeybees, they do not fly close to the ground until near their destination. They typically fly over the tree tops.