Is this a new one?
It only appears after I fill in segment 8.
It's an annoying one because I can't remove the city from my itinerary: the "back to the map" link doesn't work until you delete the errors. But if you change it out of a surface sector you get a different error. Eventually by changing the sectors around it to and from surface sectors it cleans itself up.
Also, no Jet Connect flights loaded, as far as I can see.