Here's some coverage from the New York Times about the Broadway musical It's a Bird ... It's a Plane ... It's Superman. The soundtrack is available on CD.
As you can read, it was partly written by David Newman, who also, unfortunately, also had input on some parts of the Superman movies (the stupid parts). Yes, this show is a lot like one of the sketches that used to be featured in Bob Hope specials or other variety shows of the 60s and 70s.
A certain cavalier, jesting approach was mistaken for wit. A jarring flippancy was substituted for optimism. And a cheesy, self-mocking smarminess was used, instead of treating serious things (like truth, justice, and the American way) with respect, even in "light" entertainment.