Part 2, Cobra Gunships

I have been listening to part 2 and I have questions about the cobra gunships that were acquired in 2.5. They tried to steal 12 ships but only successfully stole 9. The nine ships were piloted by: Josh, Loki, Commander Kellen, General Telles, Nathan, Robert, Gil, Aidian and Char. The ship Josh piloted was unrepairable, therefore scraped and used for spare parts. Throughout the remaining books only 4 ships were ever mentioned and eventually destroyed.  What happened to the other 4 gunships?