Note that we cannot add NOTAM-stuff into the individual OpenAir files
because for a specific map, we simply don't know whether that map needs
the 'By NOTAM'-version of this airspace or not.
The utils/extract_maps.sh script is where the magic happens (lines
58-62): this script loops over all existing map names (WEEK, WEEKEND,
...). For each map name, it loops over all individual OpenAir files
that should be in that map. If it sees a 'SEE NOTAM' line for that map,
it will add the string 'By NOTAM' to the AN-record of that airspace.
I thought this was a clean solution, but I'm open for discussion.
Regards,
Bart