During Max's post-mission debrief, Max & 99 inform The Chief that they intend to marry. However, in the previous episode, The Chief gives permission for Max & 99 to detour on their mission in order for 99's mother to meet her son-in-law-to-be. 99 sits next to The Chief on the flight to Idaho reading a bridal magazine, and The Chief is standing next to 99's mother when she refers to Max as 99's fiance. Finally, Max is surprised that Busby hasn't heard of his engagement, implying that the news is common knowledge at Control.
Max tells 99 that knows Tolliver was drugged because he said so just before passing out. However, we see Max & Tolliver's conversation right through his passing out, and he never says anything about being drugged.
When Max unlocks the restroom, it continues to say "OCCUPIED," and we hear him close the latch, and it continues to say "OCCUPIED." When he comes out, we hear him unlatch it, but it says "VACANT" the whole time.
The second time Max is sprayed by Dr. Von Shickel's toy gun his suit is completely dry in the very next shot.
A trap door in the passenger lavatory would open into the luggage hold, not open sky, even in a 1960s-era jet airliner. Additionally, any hole large enough for a man to fall through would cause a dramatic decompression in the passenger cabin.
A person falling from an airliner at cruising altitude without a parachute would make a large and distinctive mess on landing. Even an organization as inept as CONTROL would immediately realize who the victim was and what had taken place.
The pilot and copilot open the restroom floor in an attempt to drop Max from the plane. Max is still investigating the bathroom and doesn't even seem to notice that the floor is open. In real life, this would have de-pressurized the cabin and Max (along with the other passengers) would've noticed it immediately.
When Max fights the co-pilot, they forgot to add the sound effect for when they hit each other, so it's a silent fist fight.