Continuity mistake: A pilot takes Chachi up in a small plane so Chachi can go skydiving. In the long shots showing a real airplane in flight, the sky is deep blue and cloudless. In the close-ups, filmed in a studio, the plane flies through several wispy clouds, likely formed by a wind machine blowing the mist rising from dry ice.
Factual error: Joanie, looking at an issue of Billboard magazine, says, "Chachi's record has only been out two weeks and it's already #178 on the chart." Since 1959, Billboard has had a weekly "Bubbling Under" chart in addition to the Hot 100. In the 1960s, when this episode takes place, the Bubbling Under chart listed no more than 35 songs (#101 to #135). There is no way Chachi's record could be #178.