merge multiple KML track files from FlightAware into a single file that can be imported into Google My Maps

flightaware-kml-merge.py

from glob import glob
from lxml import etree


def xpath(el, path):
    return el.xpath(path, namespaces={
        'kml': 'http://www.opengis.net/kml/2.2',
        'gx': 'http://www.google.com/kml/ext/2.2'
    })


airports = {}
tracks = []
for filename in glob("2020*.xml"):
    with open(filename) as f:
        parsed = etree.parse(f, etree.XMLParser(remove_blank_text=True))
    dt, _, _ = filename.partition('.')
    date, _, time = dt.partition('_')
    root = parsed.xpath('.')[0]
    for track in xpath(root, '//gx:Track/parent::*'):
        for name in xpath(track, 'kml:name'):
            for desc in xpath(track, 'kml:description'):
                name.text = f"{date} {time} - {desc.text} - {name.text}"

        tracks.append(track)
    for airport in xpath(root, '//kml:Point/parent::*'):
        for name in xpath(airport, 'kml:name'):
            if name.text not in airports:
                airports[name.text] = airport


with open('template.xml') as f:
    out = etree.parse(f, etree.XMLParser(remove_blank_text=True))
root = out.xpath('.')[0]
nss = root.nsmap
nss['kml'] = nss.pop(None)
out_doc = out.xpath('//kml:Document', namespaces=nss)[0]
for el in tracks:
    out_doc.append(el)
for a, el in airports.items():
    if a.startswith('K'):
        out_doc.append(el)
with open('out.kml', 'wb') as outfile:
    outfile.write(etree.tostring(root))

template.xml

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2">
<Document>
    <name>N744ST Flight History</name>
    </Document>
</kml>

to print the KML URLs from the flight history page:

console.log(Array.from(document.querySelectorAll("td:first-child > span > a")).map(x => x.href + "/google_earth").join("\n"))