Yeah Joe's meltdown is a good 2 parter. The episodes missing are ones where they couldn't get music rights. Like I know in particular there's a season 2 episode where Joe & Helen kiss while because of his plot Lowell is singing "Moon River" on a walkie-talkie in the background. Here's a link about what's missing:
Alphabetti Spaghetti: All the WINGS episodes missing from Netflix/Hulu
All in all though, the show still plays well and has loads of good laughs even now.
