Adding the <gx:flyToMode>smooth</gx:flyToMode> eliminates the pause between two pins. The method is elaborated further in Smooth Touring. It looks like this:
<gx:flyToMode>smooth</gx:flyToMode>
The <gx:flyToMode>smooth</gx:flyToMode> tag goes after the gx:duration>5</gx:duration> tag:
...
<gx:FlyTo>
<gx:duration>5</gx:duration>
<gx:flyToMode>smooth</gx:flyToMode>
<LookAt>
(truncated to save space)
</LookAt>
</gx:FlyTo>
...
The default <gx:flyToMode> is called 'Bounce' and is in effect when no <gx:flyToMode> is specified:
...
<gx:FlyTo>
<gx:duration>5</gx:duration>
<LookAt>
(truncated to save space)
</LookAt>
</gx:FlyTo>
...
Or you can do extra work and put Bounce in:
...
<gx:FlyTo>
<gx:duration>5</gx:duration>
<gx:flyToMode>bounce</gx:flyToMode>
<LookAt>
(truncated to save space)
</LookAt>
</gx:FlyTo>
...
Hint: Don't do this, it's only extra work.