he automaticaly has it
go to the triet in the desert, and llyod will get taken away by desiens, and they will bring you to the ranch in the desert. Then, once you get past the mazes, then you will find two doors, try both, and the you will me Yuin, and he will call Magnus, then you fight. TIP: Let Genius learn Aqua Edge, because Magnus is fire.
2 defense curl, 7 tail whip, 10 water gun, 15 rollout, 20 bubblebeam, 27 aqua ring, 33 double edge, 40 rain dance, 47 aqua tail, 54 hydro pump
Flygon cannot learn Stone-Edge by level up, only by using TM71 Stone-Edge in the 4th-gen games.
Stone edge is a move that was invented in diamond and pearl and platinum you cannot have any Pokemon learn 4th generation moves like stone edge in firered because they don't exist. But you can migrate a aerodactyl to diamond or pearl or platinum and have it learn stone edge there.
Level 73
Level 49
Yes with tm 71
It cannot learn it by level, so the only way is by TM.
crunch double edge and dragon claw
Yes, by using TM71 stone edge. You can find it in victory road near the north part.
Earthquake rockslide stone edge
You have to stand on the pointy edge near the game Aqua Grabber (it is to the left) and you have to drill there for about an hour and when you are done, you get 1000000 coins.