Where do you get fly in Pokemon heartgold?

Answer 1

After you've beaten the cianwood city gym, talk to the leaders wife outside the gym and she gives it to you.
the hm for fly can be obtained by chuck's wife after you've beaten him at the gym
After you beat the Gym Leader in Cianwood, talk to a lady standing in front of the gym. She will give you the HM02 - Fly, Witch she will automatically give you for beating the gym leader
I got fly from one of the Gym Trainers! So I don't know where you might be able to get it.
I don't know Pokémon HeartGold/SoulSilver so much, but what I DO know is that it is related to Pokémon Gold/Silver/Crystal.

In Gold/Silver, after beating the Cianwood City Gym Leader, Chuck(Gym Leader in Cianwood City) is dissapointed, but his wife gives you the HM Fly.