To run rtlsdr-airband locally using Icecast, it is neccessary to edit the
 configuration files for both rtlsdr-airband and icecast.
 
 rtlsdr-airband:
 A good starting point is to copy the file /usr/share/doc/rtlsdr-airband/basic_scanning.conf as
 /etc/rtl_airband.conf and then edit it something like this using your own frequencies, labels and
 password. Use "localhost" as server for now and port 8000.
 DO NOT CHANGE the username "source".
 Create a directory like /home/yourusername/recordings and add it in the last part of the config below.
 
###############################
# Scanning mode example
# Single dongle, three frequencies, output to Icecast server and to a file.
# Settings are described in reference.conf
# Frequencies here are for Manchester and Leeds UK. 

devices:
({
  index = 0;
  gain = 30;
  correction = 59;
  mode = "scan";
  channels:
  (
    {
      freqs = ( 133800000, 134425000, 121850000, 118575000, 133125000 );
      labels = ( "GCC TWR", "GCC TWR2", "GCC GND", "GCC APP", "LBA TWR" );
      outputs: (
        {
	  type = "icecast";
	  server = "localhost";
          port = 8000;
          mountpoint = "stream.mp3";
          name = "GCC Tower + GCC Tower2 + GCC Ground + GCC Approach + LBA TWR";
          genre = "ATC";
          username = "source";
          password = "yourpasswd";
	  send_scan_freq_tags = false;
        },
        {
          type = "file";
          directory = "/home/yourusername/recordings";
          filename_template = "TWR+TWR2+GND+APP+LBA";
        }
      );
    }
  );
 }
);
###############################

Icecast:
All that is needed here is to change the password to that used above in rtl_airband.conf in these
three places in /etc/icecast.xml starting around line 34.
(- and + marks indicate the changed lines):

     <authentication>
         <!-- Sources log in with username 'source' -->
-        <source-password>hackme</source-password>
+        <source-password>yourpasswd</source-password>
         <!-- Relays log in with username 'relay' -->
-        <relay-password>hackme</relay-password>
+        <relay-password>yourpasswd</relay-password>
 
         <!-- Admin logs in with the username given below -->
         <admin-user>admin</admin-user>
-        <admin-password>hackme</admin-password>
+        <admin-password>yourpasswd</admin-password>
     </authentication>

###############################

Now with the dongle plugged in, enable and start the rtlsdr-airband service:

su
systemctl enable rtl_airband.service
systemctl start rtl_airband.service

...and the icecast server:
systemctl enable icecast.service
systemctl start icecast.service

Now in a browser go to:
localhost:8000
and click on the m3u play button.
Check you have a suitable antenna connected and that the volume is up.

Subsequent reboots will start both services automatically.

There are other example configs and the complete reference.conf
in /usr/share/doc/rtlsdr-airband/

Enjoy. :)