You can remove
http://raspberrypi.collabora.com/
http://repo.mutability.co.uk/
from /etc/apt/sources.list
or one of the files in /etc/apt/sources.list.d/
The other URLs should suffice for the package update information.
The URLs are not current anymore and don’t work, thus an error occurs.
These commands should remove the offending URLs:
sudo sed -i -e '/raspberrypi.collabora.com/d' /etc/apt/sources.list /etc/apt/sources.list.d/*
sudo sed -i -e '/repo.mutability.co.uk/d' /etc/apt/sources.list /etc/apt/sources.list.d/*
As an alternative you could upgrade to a fresh sd-card image, that will include the new operating system version stretch instead of wheezy what you have right now.
You can save your old the piaware-config.txt and put your current feeder-id into it.
Then you have a up to date system with stretch 
(writing sd card image described here PiAware - build your own ADS-B ground station for integration with FlightAware - FlightAware)
(For Beginners - How to Get Back Existing Station Number in A Fresh Install)