<urlopen error [Errno 60] Operation timed out>

I have recently built a small app running on Raspberry Pi / Python to help us track flights at work.
At first all seemed to go well with each enquiry taking approx 1 sec to return the data…
However over the last couple of weeks transactions seem to be taking longer ( >5 secs) and I’m getting frequent random time out errors…
<urlopen error [Errno 60] Operation timed out>
Each enquiry from the python script runs 4 Flightaware enquiries.

Anyone have any ideas whats causing these random errors to be generated ?