At 10:32 Alice is preparing dinner and is marinating and cooking a steak. When Jack comes home she says she has made a roast and you see a roast on the table.
During the very first scene, at the party, Bunny brings a tray of martini glasses with two extra stacked on top. Alice grabs one of them, the camera angle changes, and suddenly, the other stacked glass is just gone, having magically wandered into Dean's (Nick Kroll) hand.
When Frank is giving a speech in front of the band he holds the microphone like it was a modern mike. It is a Shure 55, which should be tilted back for usage. You speak into the front of that model, not the top.
The phrase "Keep calm and carry on" was not widely known in Britain, let alone worldwide, until the 2000s. While the slogan was printed on WW2 propaganda posters during the Blitz, these images weren't commonplace and only really came to be part of the public consciousness when discovered in archives in the early 2000s and subsequently used in mass media.
The setting is the 50s yet they play the song Oogum Boogum by Brenton Wood which was released in 1967.
Since they were in a simulation controlled by Frank, there is no reason for that airplane to appear nor crash in an off-limits area.