Third and final film for Edna May Oliver playing Hildegard Withers. The other two films being Penguin Pool Murder (1932) and Murder on the Blackboard (1934).
The plane at the beginning of the film flying to Catalina is a Douglas Dolphin 114, registration NC14204. It was one of four airplanes in the Wilmington-Catalina Airlines fleet at the time. It was handed over to the Army in September 1942 and subsequently shipped to Australia. On July 29, 1943 it crashed at Rose Bay, NSW, Australia and was stripped for parts. Only 58 of all variants of the Dolphin were made. The plane was also used in Living on Velvet (1935). Another Dolphin, registration NC967Y is seen at the seaplane ramp on Santa Catalina Island when the group first arrives. That plane was also in Fog Over Frisco (1934).
In the last scene of Penguin Pool Murder (1932) (the first of three films starring Edna May Oliver and James Gleason), Inspector Oscar Piper proposes to Hildegarde Withers, and they dash out the door to get a marriage license. However, the two characters are not married in this second sequel, nor were they married in the first sequel, prior to this one. In fact, there's no mention in either film of an engagement, and the characters give no indication that they've ever been romantically involved.
The Joe Slavok aka Red Smith WANTED for MAIL ROBBERY poster that Hildegarde Withers spots on the Post Office wall bears the image of RKO actor Richard Dix, only slightly disguised, but still easily recognizable. Obviously, this was an inside joke.
Willie Best is credited here by his stage name "Sleep 'n' Eat," even though his character's name is Willie. He would return to the next Hildegard Withers movie, Murder on a Bridle Path, as "High Pockets" but credited under his own name.