This armchair-continuity-expert thing is getting addictive. Moving on from The Crown to Netflix’s excellent Manhunt:Unabomber – the birth of forensic linguistics in eight parts, featuring Paul Bettany in a beard, Sam Worthington in a suit and Chris Noth in giant ’90s spectacles – the following subtitle screen appears:
Like the costumes and the hairstyles, it all seems redolently in-period. That’s the old San Francisco airport control tower, not the new one that was opened in 2016. The 747 on the right looks convincingly retro in Air China’s old-fashioned livery. But what about that plane on the left?
The lettering says “United”, but the logo on the tail, an outline globe over a blue background, is the mark of Continental Airlines – or it was, until United and Continental merged and decided, unusually, to adopt United’s name but use Continental’s livery on all its planes from then on. That merger took place in 2010: which means that this pleasingly period-looking footage cannot be more than eight years old.
How did I notice that? Just by chance. As a frequent flyer to the US, I eagerly hoard my airmiles. The obvious way to do that is by always flying with the same airline: that way, the free flights and upgrades come quicker than they would if you were slowly accumulating credit with multiple carriers. The airline I flew with repeatedly over the years was Continental: so I heard about the merger in customer emails, saw the name change on the website, nervously logged on to United’s loyalty programme to check that my airmiles had been transferred.
I had no idea that San Francisco had built a new control tower: I haven’t been there for years. I didn’t know that Air China was painting its planes to look like that well into the 2010s: I discovered those facts on Google. Now that I look into it, I’m not sure that the flowery logo on the 747’s tail is correct for the period either, or that that model of United Airbus was even around in ’95. But all this would have been a closed book to me before. I’m not an expert on civil aviation: the logo on the tailplane was the one thing I noticed.
And editing can be alarmingly like this as well. Internal inconsistencies in copy – variant spellings, bad maths, impossible chronologies – are obvious from the text. Names, dates and places can all easily be checked with other sources. But even with the highest levels of professionalism and diligence, some errors will only be spotted because you happens to know something.
Sometimes, it would need a baby-boomer editor to tell the difference between Bob Dylan and a Bob Dylan impersonator before broadcasting footage of the latter on the BBC. Sometimes, it would need a Gen-Xer to know where Luke Skywalker and Obi-wan Kenobi first met (hint: not in the cantina). These are the kind of facts that have to be known, rather than checked: there is scarcely time in a daily news routine to compare photographs of musical pioneers or rewatch Star Wars, just in case.
And sometimes, you might need a youngster – someone who understands that users change their names on Twitter for all sorts of reasons – in order not to trip over something like this:
Ten minutes past deadline 
A separate quibble with something you mentioned: airmiles. When a coworker was discussing whether she had enough miles (she had thousands of “miles”) for a free flight to Atlanta, I ignorantly pointed out that Atlanta was only 600 miles away, so thousands of airline miles should be more than enough. That’s when I learned that airline “miles” were not a measure of how many miles you could fly for free; rather, you needed many airline “miles” to fly one actual mile.
Yes, sadly! With Continental you used to have to fly 50,000 actual miles with them to get a free transatlantic return trip. (So about one free ticket every nine purchases – bit like a coffee shop loyalty card)