Both Second Life and Minecraft make use of the simulation of flying. This is a good learner activity for developing skills in hand-eye-avatar coordination before attempting more complex on-ground virtual navigation.
But it's also one of the experiences of virtual worlds that make users feel that they are competent and capable of magical thinking, so it may in itself aid learner retention.
In a highly practical way it enables someone lost in a garden or a maze to see the overall relation of parts, to stand in front of a map that says You Are Here.
For educational design this suggests creating Flyover Activities low-risk navigational learning activities to encourage confidence in users that they have a rough sense of the overall landscape before they land somewhere and start to dig, build, or consume content.
This is the opposite of what we tend to do with conditional learning activities in which we discipline learner navigation to prevent looking beyond the next bend in the road.