Interesting post. I agree with a lot of your analysis, particularly your thoughts on the WAG's odd and frankly antidiluvian attitude to air transport, but not with your solutions.
It's going to be almost impossible for the WAG to facilitate a new airline. Even if they had spare cash, (and after this week's news, we can safely assume they don't), there are very real laws in the way. The airlines at Bristol and Birmingham will object, I can tell you. If I were them, I most certainly would.
The transport links are not really the issue. I work with growing airports with far worse links. If the flights are there the people will get there. Again, there is not a chance that a road to the airport is going to get built anytime soon - there is no money, and in any case, the planning process and appeals are going to take a long time - years and years. Cf, terminal five....
As I said, it all boils down to proving to the airlines that Cardiff makes better money for them than the alternatives. No more, no less.
TA