Depends on the needed resolution. You can cover a lot more earth, far more cheaply with a satellite with several meter wide pixels.

When I used to work in remote sensing I remember that Bing Maps had a very distinct resolution transition from spacecraft to aircraft. Aircraft coverage maps were a small subset of the total earth land area, but most US towns had some coverage at that time (~2012).

As you zoomed in, you could tell when Bing switched capture methods because the aircraft cameras were clearly off-nadir, and you'd see off-angle perception differences.

They only use aircraft around larger urban areas. Satellite imagery is used for rural areas. You can see the resolution difference by seeing how far you can zoom in.

If you zoom in on a road near the pinned location for this post, and then go to, say, downtown kansas city, and zoom in you'll see a pretty significant difference.

Flying a plane around the planet sounds a lot more expensive financially and thermodynamically than just beaming down images from an object constantly falling into the views you want to see.

You are only interested in urban areas which is less than 1% of total earth surface

It's also the case that often there are more legal regulations around aerial imagery compared to satellite imagery.

I looked it up. There are some satellite images, but a lot of it is done by aircraft.

Or you could just strap a camera to a few commercial airliners and have full coverage.

You'd only have full coverage of the jet routes. They don't just fly willy nilly across the globe.

It's definitely a mix, depending on the area and the resolution. For urban places where they have 3D views and higher resolution, it's definitely planes. For a random place like this at low resolution, it's satellites.