I'm guessing you have got the Cut HM from the SS Anne in Vermillion City?
Well once you have that, and also have a bicycle, you must head to Celadon City.
Go far left and you will find yourself at Cycle Road, which is a path leading to Fuschia City.
But before you enter, if you look up there is a tree which you can cut!
Cut it, then go through the other entrance to the cycle road building. Keep going, and out the exit, and there's a house.
A girl with a Pidgey will give you the Fly HM, free of charge. :)
West of celadon city on the route you can find a tree which you can Cut down use Cut and follow the path upward and to the west go through the big building keep going until you get to a house and go inside talk to the girl and you will get HM2 which is Fly.
On the route west from celadon city you can reach a secret path by using the move Cut on a tree if you follow this path you will soon reach a house inside the house talk to the girl she will give you the HM Fly.
Cut the tree near the Snorlax outside Celadon (left exit) you will have a double battle keep heading left and speak to the woman in the house, she will give you fly.
You can get Fly on Route 16.
Here is a website that I found that can show you where all TM's and HM's are found.
http://www.angelfire.com/pokemon2/tpw30/tmhmlists/ytmhmlist.html
First, you have to battle Clay, the 5th gym leader in Driftveil City. After that, Bianca will want to battle you. If you defeat her, she'll give you the HM05 Fly. Just teach it to a Flying Pokemon and you're all set to go!
HM02 Fly is found along Route 16. Where there is, or was a sleeping Pokemon, just to the right is a bush that you can cut, pass through then there is a house. Enter to collect HM02.
get into galactic warehouse in veilstone city
I think you have to get your badge from Nimbasa town and then Bianca gives it to you. Hope I helped!
HM 2 i think
A surfing pikachu can be obtained only if you have Pokemon stadium and have a transfer pak plus you need to beat the prime cup while using your pikachu from yellow in every round. Bring other good Pokemon like mewtwo and mew.
Fly is an HM and therefore it can only be taught to Pokemon. No wild Pokemon will know Fly ahead of time.
to fly in Pokemon pearl u have to get the hm fly then u have to teach it to a Pokemon that can learn then beat gym leader
blast burn ember flame thrower seismic toss and etz
Cut, Fly, Surf, Strength, Flash.
HM 2 i think
Walk, fly, or ride a bike.
It is by the secret hideout where you get HM02. HM02 is Fly.
The sixth badgeno actually it the third badge
To acquire Group A Pokemon in the Yellow Forest route (which in this case, are the Pikachus that can Surf or Fly) you have to walk 9500+ steps to be able to encounter pikachus that can surf and you have to walk 10,000+ steps to be able to encounter pikachus that can fly.
Vermillion gym. You have to get cut from the SS Anne first.
The Pokémon that can learn Fly in Yellow are Charizard, Pidgey, Pidgeotto, Pidgeot, Spearow, Fearow, Farfetch'd, Doduo, Dodrio, Aerodactyl, Articuno, Zapdos, Moltres, and, if you use a glitch or cheat to obtain it, Mew. However, it should be noted that none of them learn Fly naturally; you need to use HM02 to teach it to them. Also, as a side note, Charizard is only capable of learning Fly in Yellow, not Red and Blue.
in Pokemon yellow there is no Pokemon stadium
You have to fly to Pewter city and go on bike and go right till you get to Mt.moon hope this helped.
To my knowledge i don't think there is a waterfall in Pokemon yellow and it is quite irrelevant to the storline if there was one. If you mean a HM named waterfall...i think your on the wrong game, only pearl and diamond have waterfall HM...i think. There are only 5 HM's in Pokemon Yellow Flash, Cut, Fly, Surf, Strength.
ya flying Pokemon can fly after learning fly