Features the return of Officer Walters (William Stevens), who frequently appeared in the first season. His absence is explained, as he transferred out of Central Division to Harbor Division, where he trained to become a helicopter pilot. One unexplained change is that while his given name in earlier appearance was Jerry, his given name now is Lou. Although Jack Hogan returns after a long absence from the series as well, he does not return as his previous character, Detective Jerry Miller, but rather a different character altogether, complete with a mustache which he was not sporting previously.
When the aircraft is in contact with Air Traffic Control, they are given a "Squawk Code". Squawk codes are four-digit codes ranging from 0000 all the way through to 7777 that are set on an aircraft transponder. These unique identifiers allow air traffic control units to distinguish between different aircraft. These work with mode A, mode C, and mode S transponders.
The first 211 - robbery - case features aerial footage of the Bank of America building in downtown Los Angeles. Though it aired in early 1974, there doesn't seem to be any indication of the taller United California Bank Building (later the First Interstate Tower and now the Aon Center) a few blocks away. As that building was completed in 1973, it seems likely earlier existing stock footage was used.
The use of "niner" instead of "nine" by Lt. Benson is to avoid any confusion in similar sounding numbers to "nine". Other such replacements, albeit not used here, are "tree" for "three", and "fife" for "five".
One of the few instances when officers are using mobile radios for police communication, in this case the officers inside the commercial skyscraper investigating the wholesaler jeweler robbery.