How do you Fly OnPokemon Platinum?

Answer 1

first you have to obtain HM01 (fly) then select the TMs & HMs pocket scroll down the list to reach the HMs select HM01 fly and teach it to a flying type Pokemon e.g staravia select a move you no longer want to keep and replace it with HM01 fly glad i helped :D

Answer 2

In Pokemon Platinum, you cannot fly freely like in later generations. To travel quickly between cities, you need to use the Hidden Machine (HM) Fly. Teach this move to a Flying-type Pokemon and then use it from the menu to fly to any previously visited location on the map.