The Great Crested Flycatcher is, well, a flycatcher. It’s a member of the Tyrant Flycatcher family which includes, among many others, the Eastern Phoebe, the Vermilion Flycatcher and the Eastern Kingbird.
In North America, most flycatchers are associated with a “sallying” feeding style, where they fly up to catch an insect directly from their perch and then immediately return to the same perch.  We watched an Eastern Phoebe establish a perch on a limb a few feet out in a pond and make endless loops back to the same perch, catching insects the whole time.
The Great Crested Flycatcher is the most widespread member of the genus Myiarchus in North America, and is found over most of the eastern and mid-western portions of the continent. It dwells mostly in the treetops and rarely is found on the ground. Just like the Eastern Phoebe that we watched, they wait on a high perch and fly out to catch insects in flight. Sometimes they may be seen hovering to pick food off of vegetation, buildings, and even windows. They also eat fruits and berries. 
All adults are brownish on the upper parts with yellow under parts; they have a long rusty brown tail and a bushy crest. Their throat and breast are grey.
Their breeding habitat is deciduous or mixed forests across eastern North America. They nest in a tree cavities, but will also nest in a properly sized bird house in urban environments. Usually a snake skin is included in the lining of the nest, but sometimes a plastic wrapper is substituted. 
Cornell says “The Great Crested Flycatcher is a bird of the treetops. It spends very little time on the ground, and does not hop or walk. It prefers to fly from place to place on the ground rather than walk.” 
References and Additional Information
 Wikipedia: Great Crested Flycatcher
 The Sibley Guide to Birds, second edition – David Allen Sibley
 Cornell – All About Birds: Great Crested Flycatcher
 Cornell – All About Birds: Great Crested Flycatcher – sound
 The Breeding Bird Atlas of Georgia – UGA Press: Schneider, Beaton, Keyes and Klaus, Eds.
 Wikipedia: Tryant Flycatcher