"The Eagle" was inspired by Alfred Tennyson's explorations through the Pyrenees region of southern France, which began in his early twenties. But the poem features another kind of exploration: it allows us to see the world from the eagle's perspective. The high cliff and the sky are depicted as part of another world, one that is nearer to the heavens than to earth. The eagle has no competition in his domain: he flies around like he owns the place.
The speaker projects his own tendencies toward exploration onto the eagle. In fact, the eagle isn't really much of an explorer, but the speaker wants to think that his own travels imbue him with some of the eagle's grandeur and nobility.