Satellites are very limited.
They run on polar sun synchronous orbits. In the early morning and evening, when they have good shadows to give 3D information.
So their presence runs to a timetable and anyone on the ground just needs to throw a tarpoline at the appropriate over anything they want to hide.
The KH 11s (and KH 12s, which are the stealth version) have finite manoeuvre fuel to correct their orbits or to move to new orbits. So they are pretty much stuck with what they can see.
In the Falklands war the Americans changed the orbit of one or more of these satellites to give us photo intelligence, using up the manoeuvre fuel and very significantly shortening the satellites lives. Considering that they cost over $3 billion each in 2013 dollars this was a huge gift from the Americans to us.
Reconnaissance drones are still very limited. They are only really any use in tactical situations in uncontested airspace. The Iranians regularly shoot down USA and Israeli drones.
Aurora was a black project, like the F-117, kept secret from the public. Forensic accountants found how it was funded, so we have multiple sources of evidence of its existence. It managed to come into service then out of service whilst still remaining secret. It is thought that there were major problems with it, shortening its service life and leading to the SR 71s coming back out of retirement.