Heathrow google earth only two planes
 

Has someone at Google earth sat and painted out almost all of the planes at Heathrow and at other major airports.

Many, possibly most, major airports are similar on GE.

So do they paint the planes out or combine photos.

Turn on "Historical Imagery" under the "View" menu.

You'll notice even fewer cars on the M25 if you pan a little west. In fact, anywhere.

As i understand it google combines multiple images and compares for objects that move. Same way that we can look for asteroids, incidentally. If the image is the same, nothing is moving. If the image is different, something moved and the live version will be the one not showing a plane (in this case). Any aircraft, or other vehicle for that matter, will be visible if it was there during multiple camera passes. They dont just airbrush out anything that looks like an aircraft.

If you have a look at parking markings at gates, you can see some of the quirks!