Gex's mother lends her son a shuttle in Gex 3.In the final level, Gex start the level in a space shuttle near Rez's space station. Gex's mother probably still owns 51% ownership of NASA since the family is still rich from the inheritance from Great-Uncle Charlie. So she allowed Gex to use one to stop Rez. She may or may not know Rez is her husband.
The Gex series will be revived sometime during the next generation.Because look at all the revivals that have occured Rayman, Spyro, Adventure Island, Donkey Kong Country, etc. It won't surprise me if the Gex series gets revived as well. Rumor is that a 4th title was in production but later cancelled. Therefore it's highly possible that a new developer [my prediction UbiSoft] will complete the project and depending on the games success may ultimately revive Gex.
Gex's ultimate fate in the event of a Game Over......is becoming the Geico gecko. Obviously after mellowing out a lot.