We have bought Robohelp license to generate the help files. We are thinking of considering to use ".air" output format as opposed to the "Webhelp" format. My team wants to know if our clients will have to purchase any special licenses for installing the ".air" help application individually.
I believe that all that they need is the air runtime, which is free to be able to use it.
Indeed all the users will need is the free AIR runtime.
The only other possible expense would be to purchase a Digital Certificate from somewhere such as THAWTE or VeriSign. But only if you care to provide a signed and verified digital signature.
Helpful and Handy Links
Just wanted to point out that AIR is installed locally whereas WebHelp would go on a server. Thus it has to be installed on each user's PC. You cannot distribute the AIR runtime unless you have the freely available licence for that.
There is a browser version of AIR that does not need the runtime but it also lacks some features. It's all explained on my site.
See www.grainge.org for RoboHelp and Authoring tips