"Eight Is Enough" S3:E27 Marriage and Other Flights of Fancy Part 2

The single strangest "Eight Is Enough" episode, it includes only one Bradford (David), lots and lots of hang gliding, and a rivalry between a young hotshot glider and an older retired Air Force pilot who are never mentioned again in the series.  At least most of the first part episode not only had the Bradfords but the well-worn plot elements of David and Janet fighting about her career as a lawyer and Tom Bradford unknowingly promoting pornography (he finally gets a short story published, but it's in the Playboy stand-in "Man's Man Monthly").  I can't tell if the episode is supposed to be a backdoor pilot or if one of the producers really, really wanted to promote hang gliding as a sport.