How in the world can you get a Pokemon to FLY?

You teach the Pokemon FLY, then go to that Pokemon in your team, choose FLY, and choose where you want to FLY to.

Go to your HM + TM case and click on Fly. Teach it to a pokemon. Then go to your list of Pokemon and click on the one that knows fly. Then click fly and click on the town you want to go to. Its not that complicated

First teach it to a Pokemon that can learn it. Then while you are outside in a city or on a route access the menu and select Pokemon. There will be a list of your party, click on the Pokemon that you taught fly to and the list of actions will come up. Example: Summary, Moves, etc. It should say Fly at the top above summary. Select Fly and the world map will be displayed with your sprite on the map to show you where you are and there will be a cursor so you can move the cursor, not sprite, to where you want to go. Once you confirm your destination, the Fly sequence will occur and you will go there.

Open your menu and go to your Pokemon. Select the Pokemon that knows fly and select fly. Then choose your city to fly to.

Just click on the Pokemon that knows Fly and then click Fly and select the place you want to go.