On the old BD of Airplane!, there was a boom mic visible in two shots in the mirror during the scene whenever Kramer’s wife is talking to Paul in Kramer’s house that was (poorly) digitally removed, however oddly enough on the new 4K remastered BD, the boom mic was restored along with a small portion of the mirror frame that was accidentally erased on the old master as a result of the sloppy removal
https://caps-a-holic.com/c.php?a=1&x=83&y=53&d1=14736&d2=14733&s1=152852&s2=152814&l=0&i=12&go=1
but yet bizarrely enough on the same 4K master, the wires used to throw around the beating heart in a scene towards the beginning of the movie were digitally removed that were visible on the old master