The fact that data is in the public domain does not mean that one can make unrestricted us of it. Given that the purpose behind publication is to comply with an international treaty obligation under ICAO the NAAs would be quite entitled to place legal restrictions on its use for other purposes. The copyright in the AIP remains with the NAA (i.e. the CAA) and they can license it however they wish. Ditto with anything else put into the public domain, unless the owner makes it clear that unrestricted use is allowed.
I have no doubt that incorporating data from the AIP into a piece of software, whether open source or otherwise, would be a breach of copyright and restrained accordingly.
Last edited by Justiciar; 25th Aug 2010 at 14:51.