Sorry for reaching into the past again, but this just got me thinking about a really "sooty surprise" I got at JFK the summer of 1971.
Before embarking on that trip I'd heard about Northeast Airlines and even received a scale model of their 727-200. Bright canary yellow, that was! When I finally saw one of them in person, I was really taken aback. The entire rear portions of several of their jets were jet black (pardon the pun). I then christened them "Northeast Dirty Birds."
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Photo © Willam W. Sierra