airports before the 1960s

[pjank42]

As long as the airports with the same IATA code are not from the same time period, we can use the from and to-tags to specify when it is operating and that way it doesn't matter if they are the same:

Code:

<airport name="Denver International Airport" icao="KDEN" iata="DEN" type="International" season="All_Year">
   <period from="2/28/1995 12:00:00 AM" to="1/1/2199 12:00:00 AM" />
   <town town="Denver, CO" country="122" GMT="-06:00:00" DST="-07:00:00" />
   <coordinates>
     <latitude value="39°51'42''N" />
     <longitude value="104°40'23''W" />
   </coordinates>
   <size value="Largest" pax="52600" cargo="Large" cargovolume="236" />
   <terminals>
     <terminal name="Jeppesen Terminal" gates="201" />
   </terminals>
   <runways>
     <runway name="07/25" length="3658" surface="Concrete" />
     <runway name="08/26" length="3658" surface="Concrete" />
     <runway name="16L/34R" length="3658" surface="Concrete" />
     <runway name="16R/34L" length="4877" surface="Concrete" />
     <runway name="17L/35R" length="3658" surface="Concrete" />
     <runway name="17R/35L" length="3658" surface="Concrete" />
   </runways>
 </airport>
   <airport name="Stapleton International Airport" icao="KDEN" iata="DEN" type="International"
          season="All_Year">
   <period from="10.17.1929 00:00:00" to="02.28.1995 00:00:00" />
   <town town="Denver, CO" country="122" GMT="-06:00:00" DST="-07:00:00" />
   <coordinates>
     <latitude value="039°46'45''N" />
     <longitude value="104°52'55''W" />
   </coordinates>
   <size value="Very_large" pax="29232" cargo="Smallest" cargovolume="0" />
   <terminals>
     <terminal name="Terminal" gates="60" />
   </terminals>
   <runways>
     <runway name="7/25" length="1484" surface="Concrete" />
     <runway name="8L/26R" length="2621" surface="Concrete" />
     <runway name="8R/26L" length="3049" surface="Concrete" />
     <runway name="17L/35R" length="3658" surface="Concrete" />
     <runway name="17R/35L" length="3505" surface="Concrete" />
     <runway name="18/36" length="2362" surface="Concrete" />
   </runways>
 </airport>

For the ones missing IATA code it would be ok to add a custom made one as long as we don't have overlap with an existing one.

I hope I answered your questions :-)