My father spent a few years flying cargo with Beech 18 in the 80's and the reqs from the FAA were stringent due to age. So some parts were new creation while others were salvaged from air frames kept for just that. I flew with a collector of antique planes and low budget warbirds a few times my father was friends with. When he bought T28, he bought 3 so he could keep one flying by having the other two deconstructed and two refurbished engines in storage. To have his PT19 passed off air worthy, about the only original parts left were the info plates. He still ditched it in a corn field the first day it was out of the hanger, he was a so so pilot but, he was a millionaire retired IBM engineer. He bought the land from the farmer on the spot and had him help put up a quick barn over the PT19 to hide it from the FAA and cut down all the corn to cover up the landing mishap. He let the farmer keep growing corn on the rest of the acreage and profit from the harvest. Then paid him to bulldoze a dirt strip up to the barn the next spring when he flew it home after all the stealth repairs were finished. Having money and it being the 80's you could get away with that.
