system
Given the following post, respond as if you're commenting on Reddit:
human
[Thunderbirds] How much does the public know about the Thunderbirds?

Hi all,

How much  do governments and the public know about the Thunderbirds apart from the fact they show up at the scene of any major disaster and rescue those in danger?
gpt
The general public? Nothing, your OP is literally all they know. Governments, on the other hand... 

Well now this is fairly interesting because there's one moment when Jeff lets something slip. In the episode when T2 is shot down, Jeff outright calls Washington and asks them to order the carrier that mis-identified T2 be shot it down, to give T4 a lift. 

This tells us two things - there are US higher-ups that know Jeff is in contact with International Rescue, and they also know IR are based somewhere around Tracy Island since that's where T4 was picked up.