She is thought to have quit over frustrations surrounding the funding arrangements behind Iostar, which is being positioned as both a producer and distributor of content.
One source suggested that Iostar was now developing into something that more resembled a venture capital player rather than a company that was serious about making investments in content.
Airey is said to have expressed doubts over its ability to live up to its original vision.
Her swift departure raises questions over the future of Nick Milligan, the managing director of Sky Media and a close ally of Airey. Milligan had been expected to quit Sky, with Iostar one of the potential options on the table. However, he remains with Sky and is working with advertisers on the implications of the collapse of its carriage deal with Virgin Media.
Iostar claims it wants to be one of the world's leading content distributors and producers. It launched its distribution arm at the recent MIP TV festival in Cannes.