Tornado-1

The Tornado-1 (トルネード号) is a biplane owned by Miles "Tails" Prower. Possibly based on both previous Tornado and Tornado 2 biplanes, but upgraded with better designs, it is first seen in Sonic Unleashed.

Sonic Unleashed
In Sonic Unleashed, Tails offers Sonic the use of his Tornado-1, although this is not to be confused with the original Tornado. It is a newly-built Tornado plane with a more futuristic design. This plane has writing that reads "Tornado 03" near the rear, which can be seen when it transforms during both of the Tornado Defense Acts of the 360/PS3 version. The Tornado-1 also combines features of previous Tornado incarnations: the red paint job and outward construction of the original Tornado, the ability to transform into an X-shape like the Tornado 2, and the homing missiles found on the Cyclone from Sonic Adventure 2.

Sonic Generations
Tornado-1 has made brief appearance in Sonic Generations, where Modern Tails once again uses this version of the plane to race against Modern Sonic in the Challenge Act "Tails: Way Past Fast" in Green Hill. During the whole Challenge Act, Tails uses its normal biplane mode and not its enhanced Battle Mode transformation.

In the Speed Highway, one of billboards on buildings is featuring Tornado on its standard form with slogan "faster than airmail". It is also shown on a billboard that is advertising for "SONIX Delivery Service".

Mario & Sonic at the Sochi 2014 Olympic Winter Games
The Tornado-1 will make a cameo appearance in upcoming Mario & Sonic at the Sochi 2014 Olympic Winter Games in one of the bobsleigh event set in Speed Highway on a billboard that reads "faster than airmail", which almost is identical to one from Sonic Generations.

Trivia

 * A new Tornado was made by Tails before the events of Sonic Unleashed, although unlike the other Tornado models it was introduced with little fanfare. It is called the Tornado-1 in the English script, referencing the events of the Sonic Adventure games. However, it is instead known as the Tornado-gou in the Japanese script and in Tails' Japanese profile. Regardless, it is identified as the Tornado 03 on the craft itself, which may be another acceptable name.