FBI Spy Planes

I understand, agree, and am even thankful for the fact that the FBI needs/uses aerial surveillance.

But why does the FBI and DEA register the planes to fake companies?

http://www.nationalsecurity.news/2015-08-17-fbi-using-fake-shell-companies-to-fly-spy-aircraft-over-cities-equipped-with-illegal-snooping-devices-that-spy-on-americans.html

http://talkingpointsmemo.com/news/fbi-air-force-surveillance-fake-companies

http://theantimedia.org/investigation-reveals-dea-flying-surveillance-planes-in-us-using-fake-companies/

And possibly fake people?
"Included on most aircraft registrations is a mysterious name, Robert Lindley. He is listed as chief executive and has at least three distinct signatures among the companies. Two documents include a signature for Robert Taylor, which is strikingly similar to one of Lindley's three handwriting patterns."

This AP link has a list of the fake companies:
OTV Leasing
OBR Leasing
PXW Services
KQM Aviation
LCB Leasing
NBR Aviation
FVX Research
RKT Productions
NBY Productions
PSL Surveys
NG Research