You have to defeat the Driftveil city gym leader, Clay, the head off to route 6 and Bianca gives it to you. Hope this helped :)
reshiram thunderus tornadus landours
You need to get the TM and teach it to a pokemon
You need a flying type that knows HM Fly
You will obtain fly when you beat the fourth gym.
Archeops can learn fly
Yes Sigilyph can learn fly
you dont
Go in the pokemon section of menu. Tap a pokemon that knows the move fly. tap on fly. Choose an area, and it will fly you there, as long as you've been to the area.
HM 02 is fly in black and white
After you beat the 5th gym Bianca, she will give you the HM02 Fly
i would say soulsliver becase on soulsliver you can fly and black you cacth water pokemon but on sliver you can get fire pokemon
to get to the pokemon league either go through victory road or fly to there