I came across PBA on my first visit to Boston, from the UK, in 1982. Apart from the variety of Cessnas, they operated Martin 4-0-4s and DC3As (the YS-11s came later). Some of the DC3s were ex American, 1930s vintage machines with the right hand rear passenger door.
They did "Snowbird" down to Florida each winter and had a very successful operation.
By 1987 they had been eaten up by the Trans Texas empire and three visits to Miami between the fall of 1987 and the Spring of 1988 yielded dozens of shots of Eastern DC3s (the only spoiling of the illusion of a continuum of Eastern DC3 operation were the PB suffixed registrations and the "Express" titles - hardly the word to apply to the venerable 3s). Yes the PBA machines were still in service, including the right hand door machines.
Without going into the loft to check the archive, I seem to remember that N136PB was, at the time, the oldest commercial airliner in regular, scheduled, daily service in the USA, dating from 1937!
In the summer of 1988 I was across the Atlantic again and visited Hyannis. There were quite a few interesting aircraft on the old PBA ramp including a number of incomplete DC3As and YS-11s in PBA colours and a magnificent Beech 99 in full Continental Exprress livery.
I got talking to the senior engineer who was from Southend, in the UK. He had gone to Egypt with some HP Heralds when they were sold to Pyramid Aviation and had stayed on when that airline bought YS-11s because of his RR Dart knowledge. He stayed with the YS-11s when they were sold to the States! Well I suppose its one way of keeping in work!
When I was last on the Cape in 1996, Cape Air were doing a great job and even had Cessnas in overall advertising schemes. The morning line up at New Bedford, Hyannis, Nantucket and all the other points served still took place, the breakfast bacon and pancakes in the various airport cafes were still the same but the lack of the white seagull on a blue background and the friendly PBA How are ye? was long gone.