The Toyota Aqua Air concept car was unveiled at the Tokyo Motor Show recently, and it has set Prius detractors spinning. Car enthusiasts note that the design of the Prius doesn’t exactly blow your hair back, but the topless version of the ultimate hybrid is going to do just that; it’s a convertible!

You may also know the Aqua as the Prius C, and it was shown alongside three other versions of the Aqua-Prius. The Cross courts those adventure junkies who are after a car with a little more off-road potential. The Premi is the luxury version and the Sports aims at the sportier, racing types who are after a little flash as they show off their driving skills.

As other hybrid vehicles have entered the competition, Toyota plans to remain a front-runner. The anticipated Next-Gen platform, according to Mitsuhisa Kato, Toyota global research and development executive vice president, employs an assault on two fronts. First, the Prius is going on a diet, reducing weight by as much as 20 percent. Second, comes increased engine efficiency for hybrid (by 1 to 4 percentage points) and non-hybrid (by as much as 3 percent). The improvements go by the moniker Toyota New Global Architecture (TNGA).

All of this action however, is overseas. What about the US market? The current debate as of the LA Auto Show is whether or not the hydrogen fuel cell Toyota intends to launch in the US in 2015 will bear the Prius name? Toyota marketing executive Bill Fay says the decision is yet to be made but the company knows what a valuable brand it has, “People equate Prius to a lot of things, it has a positive name out there regarding technology, innovative products and environmental friendliness.”

Fay also reminisces back ten years to the premiere of the Prius, “everyone was like ‘what is this thing?’ and now we’ve sold five million hybrids.”

The hydrogen powered FCV concept was revealed at the Tokyo show, which opened last week.

[Image via Toyota Global Facebook.]