On <a href="http://www.flosm.de/html/POI-Karte.html">http://www.flosm.de/html/POI-Karte.html</a> I noticed that Dusseldorf & Schiphol have the tag<div><br></div><div><div>aerodrome = international</div><div>aeroway = aerodrome</div>
</div><div><br></div><div>Zaventem only has</div><div><br></div><div>aeroway = aerodrome</div><div><br></div><div>But it might be better to contact the creator of openbusmap (see Legal Info/License) on the website and ask which criteria he is using.</div>
<div><br></div><div>m.</div>