Flygon is one of the several dragons left to UU, outshined mainly by Garchomp in OU, who is better in pretty much every way. However, in UU Flygon can once again shine like it's late Gen IV again. Great Dragon/Ground typing set Flygon apart from the pack of dragons in UU, giving it a great offensive combination of STABs (unresisted in UU). Immunity to both types of Spikes and resistance to Stealth Rock and decent defensive stats and typing give Flygon some staying power, especially with Roost added to the equation.
Flygon@ Choice Scarf/Choice Band
4 Hp/ 252 Atk/252 Spe
Standard Flygon set that let it shine as a scout and revenge killer. Jolly is less necessary than it was in OU because of a much less populated speed tier. Choice Band lets Flygon hit quite hard with such great STABs.
4 Hp/ 252 Atk/ 252 Spe
-Roost/ Stone Edge
Physical Life Orb works very well because of Flygon's great coverage in UU, as well as Roost to recover lost health. Hone Claws is Flygon's only boosting move, and can be used pretty well Flygon's speed, but isn't completely necessary to get Flygon to sweep.
Flygon@ Life Orb
80 Atk/ 252 SpA/ 176 Spe
Mixed Flygon. Draco Meteor hits hard even off of Flygon's 80 SpA, and Fire Blast clears physically defensive Steels and one's using Air Balloon, as well as Chlorophyl sweepers.