You need to have beaten Maylene (the fourth gym leader who is in Veilstone) to be able to use fly.
You need the Thunder Badge.
You can use the GTS in Pokemon Platinum after you get the first gym badge from the Oreburgh City gym.
To use the HM Fly, you have to have the Thunder Badge, won from Lt. Surge in Vermilion City.
You will need the 7th badge to use the move Rock Smash.
It's badge 7
You need the Thunder Badge.
The badge from Cianwood.
You can use the GTS in Pokemon Platinum after you get the first gym badge from the Oreburgh City gym.
To use the HM Fly, you have to have the Thunder Badge, won from Lt. Surge in Vermilion City.
it's the 3rd badge!
In Pokémon Emerald, you can use Fly after earning the Feather Badge from Winona, the Gym Leader of Fortree City. This badge allows you to use the Fly move outside of battle, enabling you to travel quickly to previously visited locations. Be sure to have a Pokémon that knows Fly in your party to utilize this feature.
You can use the move as soon as you get it. You can fly to different towns with a certain badge.
NO
You will need the 7th badge to use the move Rock Smash.
In Pokémon Diamond and Pearl you must defeat Maylene in Veilstone City's Gym and receive the Cobble Badge, this will allow you to use the HM Fly outside of battle.
It's badge 7
get the 4th badge in celadon city