But if the argument is that a pilot in any old plane or helicopter could see a thing, and therefore there is no expectation of privacy, that's a bit different (don't you think) from saying that since a spy satellite that can count troops in formation from fifty miles away can see the thing...
If that argument is inherently different, then now we are talking degrees of difference.
Those degrees may matter.
Should you not expect privacy if you can't hear or see the helicopter or plane?
Note that courts have already ruled against police who wanted to be allowed warrantless use of infrared to watch people in their homes at night. If it couldn't be seen by unaided sight, then it should have an expectation of privacy, I believe was the logic behind those rulings.