Typing: Ground/Dragon --> Ground/Flying
Ability: Levitate --> Sand Stream
Stats: 80/100/80/80/80/100 --> 80/140/80/115/80/125
New moves: Brave Bird, Air Slash, Hurricane
Sand Stream takes the flavor from Flygon's many Pokedex entries, which often say the it stirs up sandstorms. The Flying type keeps Flygon true to its name and gives it powerful STAB in Brave Bird. Flygon can play as a nice offensive support Pokemon and momentum provider thanks to its access to U-turn, Defog and Roost and can hold its own in battle with good offenses that match the power of Life Orb Flygon's. (For clarification, Hurricane's accuracy remains 70% in Sand and Brave Bird fits for Flygon even though it is not a bird: "The user tucks in its wings and charges from a low altitude. This also damages the user quite a lot.")
Typing: Ice
Ability: Solid Rock
Stats: 80/80/80/80/80/80 --> 80/120/120/80/120/60
New moves: Icicle Crash, Recover
Mega Glalie is mostly made to be a bulky Spikes setter. Solid Rock helps to compensate for its typing and it has gained solid bulk with good attack. It has great tools as a lead, such as Ice Shard, Recover, Taunt, Explosion and Super Fang (with Crunch and EQ to cover the two normal moves) and can stay alive throughout the match with Recover, bulk and weakened weaknesses.