Re: "no redundancy in the internet link"
It is pure and utter design failure.
Why have 100's of systems download flight information from the cloud ? <---- that is already brain-dead, somebody in the design team has never heard of multiplications!
No resilient internet connection ? <---- that is brain-dead
Caching is not the answer to a fundamental failure of resilient network design.
It reduces internet traffic significantly and buys you time for the connection fail-over..