I got data out of Wikipedia for about 3800 airports. I have entered about 2300 in OSM so far. For each one, I'm finding it in the Landsat photos, adding the aerodrome node, and adding the main runway(s). And, of course, eliminating any duplication. I've learned the name for airport in quite a few languages now.

I'm getting good at reading the false-color images in some Landsat areas. It looks like some multi-spectrum combination in a lot of areas.

For some areas, the Landsat data contrasts better than the Yahoo visible-spectrum-only photos, even seeing through some light cloud cover occasionally. In fewer cases, the Yahoo photo has better contrast.

Yahoo doesn't have very good resolution for very much outside of the US, at least for the images available to JOSM through YWMS. Landsat is usually a little sharper. They aren't always aligned with each other. But for something as coarse as a runway in a sparsely-mapped area, either is good enough.

Only 1500 more airports to go....