Based on the provided text, it is unclear what the functionality and purpose of Calculator Air is. The text describes a page on the App Store where users can read reviews, view customer ratings, and download the app onto their iPhone, iPad, or iPod touch.

However, there is no information given about what the app actually does or what type of calculator it is.

It is possible that the app is a basic calculator for performing simple arithmetic calculations, or it may have additional features such as scientific or financial calculations.

It is also unknown if the app is free or requires payment to download and use.

Without additional information, it is difficult to provide a thorough and informative description of Calculator Air.

However, based on the available details, it can be assumed that the app is a tool for performing mathematical calculations on Apple mobile devices.

Users may be able to benefit from its features and functionalities, as well as from the reviews and ratings provided by other users on the App Store.

Ultimately, more information is needed to provide an in-depth and comprehensive description of Calculator Air.