Here's a fic idea that I picked up after listenting to the theme songs
of both.

2 Evil orginizations combine forces to help take over the earth. The
only people that can stop them are the Tracy family of International
Rescue and the Science Ninja Team

A X-over between Thunderbirds and Gatchaman(Battle of the Planets)

It has been so long since I saw Thunderbirds I can't fo it. So I offer
the fic idea up for anyone who wants it.