Tornado

Tornado (トルネード, Torunēdo) is Tails' Final Smash in Super Smash Flash 2. Tails jumps up into the Tornado biplane while saying "Leave the flying to me!" and his perspective changes similar to that of a shooter game. During the transformation, you can shoot rapid-fire bullets or bombs. The bullets deal 3% damage each with low knockback, and the bombs deal 20% damage with high knockback.

Origin
The Tornado is a plane constructed by Tails prior the event of Sonic the Hedgehog 2, game where it made its first appearance. Since then, it has been featured in many other Sonic games. It is typically piloted by Tails, while Sonic or other characters walk on its wings. The plane is owned by Sonic himself, and as such he has also been seen to be the pilot at times. Often, in the Sonic series, it is shown towards the end of each game where it usually arrives just in time to save a character from falling to his or her death. It has since become a staple icon of the series.

It's noticeable that the Tornado that Tails' uses is closer to the design of the Tornado 2, even though it doesn't need the power of the Chaos Emeralds to work in SSF2.