There are two ways to approach this. One way is as Americans would, laughing at the obvious flub, and smiling, knowing that Trump fully realizes there were no airports in the 1700s.
Then there are partisan hacks (who apparently have never made a mistake). The same thing happened with Dan Quayle's great Potato Misspelling Disaster back when I was in college. I remember it well, because even though it was before cable news and the Internet, the press/entertainment industry kept pounding and pounding and pounding Quayle over it. My roommates and I - non-religious, Democrat and liberal all - finally said enough. The guy goofed, big deal. We don't need to call the United Nations because of it.
Contrast that with how the press covered Biden, who only now, as the press considered going full blown socialist/Marxist in a candidate, has ceased leaving him alone, despite years of having a shoe dangling out of his mouth as if it was grafted there.
Of course to circle the tribal wagons, the really lame partisans will suggest that pointing out Obama's 57 states is some sort of 'oh yeah!' trick. Fact is, I hardly ever hear anyone bring that up, unless it's to counter something like this that tries to suggest Trump is a moron and idiot and dolt and stupid because he - made a mistake! It points out Obama and others make mistakes, too, and we don't call them morons.
As one who used to speak publicly for a living, I can tell you that you eventually make a gaffe. It happens. Sometimes you have to back and correct yourself, sometimes you do try to explain what happened, sometimes you just smile and move on. But if a person tried to suggest the mistake proves something about your person - which they almost never did, being sane people - you obviously would try to set the record straight.