Why does the clue give them specific instructions for flights? Like the connecting flight. From the show they make it seem like they have to find their own flight.
I'd guess because in the very early seasons, back when teams had free reign to book their own flights, we had incidents where a team would botch it and end up almost a day behind, or adversely sometimes in their favor, almost a day ahead of everyone else. Also to avoid any risk of them accidentally transferring through somewhere they shouldn't for safety reasons.
They don't really want things like that anymore, better to keep them all moderately bunched together.