Warbird Information Exchange

Airplanes like the B-17 never had civil production certificates and were never officially civil "types." Thus, the limited type certificate (LTC) program after World War II to allow specific surplus miliary airplanes to be operated as civil airplanes when modified according to the approved standard.

The 1935 Boeing 299 had an experimental civil license but was never certificated.

I missed the thing about the FAA grounding warbirds. I did hear, though, that they expect airplanes to have a basic level of airworthiness before people fly them.