It is very exciting to see this here! I have been a beta tester for OnAir for about two months now (started when they first made a little announcement about a closed beta on another forum) and it has been an absolute pleasure being a part of it. Not only is OnAir so much more of a complete airline management program than others I have used (as already described by Mathijs), but Antoine and the dev team are brilliant at what they do. They have listened to feedback and suggestions (and already implemented many), they are able to fix bugs very quickly and they always respond to posts on their forums and let us know what they are up and how they are progressing with development. Since the start of the closed beta, there have already been 8 updates (just about one per week) with substantial changes, improvements and bug fixes.
I am very much looking forward to the continued development of OnAir and also to see all the new people that will surely be pouring into the OnAir world after this announcement here!