The lower stage on the right side of the stage select screen. This stage is big and open with lots of places to fall to your death. Watch your step. Head to the right, past the Sky Claws and onto the moving platforms. You can ride these up, but let's take a detour to the right.
Next to the enemy is a funny looking wall with flames marked on it and the letters "DA." These walls can be destroyed, and sometimes are hiding helpful items, so if you feel like sinking enough shots into them, they may be worth your while. Head back to the moving platforms.
Go as high as you can go on these platforms and then dash jump all the way to the left to the spot above the start of the stage. There's a Heart Tank here waiting for you.
Head back to the top of the moving platforms and on to the giant "AIRPORT 1001" sign. Feel free to blow up some of those special walls on the way up. You'll meet some Gun Volts and Turn Cannons on special pillars that raise and lower to block your path. Destroy the Turn Cannons to drop the pillar into the floor.
When you reach some vertically moving platforms, use them to go left instead of right. Break the glass to reach the Sub Tank inside. You can also kill the Gun Volt in here for a cool effect. Head back to the right.
Standard short-range flamethrowers that take up valuable platform space. Destroy them with charged shots before you get burned to steal their platforms and proceed.
Keep going right and taking out Flamers. When you reach a destructible wall here, blow it up for a 1up. You'll have to do it by wall jumping, shooting, and reattaching to the wall, though.
When you have to climb a tall pillar and hop into a nearby ledge, go under the ledge and destroy the wall instead to find another upgrade capsule. This one gives you the Head Parts, which let you destroy specific blocks with your head. This is actually not very useful, but you'll need it to get a couple of really cool things later, so you might as well grab it and head back to the ledge.
When you see a 1up, you can reach it by going right past it and then up and back to the left. Otherwise, take out the Metalls, Sky Claws, and Balls De Voux and proceed right. You'll reach some platforms that will fall when you step on them so don't linger. You'll reach the airship and Storm Eagle.
Storm Eagle's room is big and open and doesn't have any walls. A bird has to fly free. He's pretty easy to take down with just the X Buster and leg upgrade.
The Hard Way
Storm Eagle can flap his wings to blow wind to try to push you off the stage. Run towards him to prevent that from happening. You can dash to make things easier. When he flies up into the air to dive bomb you, run (but don't dash) to avoid it and quickly turn and unleash a charged shot to counter it. He can spit out eggs that hatch into four birds that will fly at you. This is another thing easily dealt with using a charged shot. When he fires his giant wave of wind weapon, notice that it doesn't actually hurt you, it just pushes you like the wind from his wings except faster. Dashing works here, too. He's not a very tough boss since half of his attacks don't actually hurt you.
The Easy Way
Exactly the same as the hard way except shoot him with the Chameleon Sting to do more damage than your regular shots without charging. You'll get a pretty handy weapon for winning.
Like Storm Eagle's tornado weapon, except it actually does damage. A tunnel of wind moves all the way across the screen, passing through walls and even shields to an extent. It doesn't take much energy to fire, either. Feel free to just have this equipped all the time. If you charge it with the arm parts, you'll create a short-lived vertical pillar of air that can pass through ceilings and floors.
If you've already beaten Flame Mammoth, you might want to go back to his stage to get the arm upgrade using your lame new helmet. If you're following the guide, that's where we're headed next anyway.
NEXT: Flame Mammoth