you get it at Cianwood city. Beat the leader (chuck) His wife outside will give you the HM.
Teach a Pokemon Fly after obtaining the HM and choose fly when you select the Pokemon.
No Gastly cannot learn fly in Pokémon HeartGold.
Obtain it from a gym leader.
yes you can. you can fly back to the indigo plateau and then you can enter the Pokemon leagues again.
Cianwood city after defeating chuck
same just touch screen.
You can fly there or go west.
you get hmfly in heartgold after beating chuck the 5th gym leader who uses fighting type in cianwood city..
There is no best Pokemon on Pokemon HeartGold.
there is no Pokemon Mansion in Heartgold.
dont need one just fly to pkmn league and then u can fly to any reigon/city
They are not in Pokemon HeartGold