FS9 compatible paints have now been added for Frontier. You can find the FS9 download links on the individual blog posts for the respective aircraft type HERE
These FS9 paints were generously converted by user Danthepilot on the AIG Forums. Special thanks to him for his efforts. Any questions about conversion or issues with the converted files can be directed toward him.
Hopefully more converted FS9 paints will appear on the site in the future! Any future converted paints will appear under the ‘FS9’ category on the right hand side of the page, listed with the airlines. Keep your eyes peeled!