There are errors in this. Just glancing at it. MIA is Miami. Toronto downtown is YTZ.
xkcd is really smart so maybe the joke is just going over my head...
Usually
@Achas Veachas would explain xkcd jokes around here. (Let's see if the genie pops out of the lamp.)
ETA: Okay, now that I read the left column I see that it's supposed to be a joke. Like ORD being Orlando and SAN being listed five times. Ha ha. I get it.
Not funny.