Antigen tests don’t amplify their protein signal, so they are inherently less sensitive. To make matters worse, that signal gets diluted when samples are mixed with the liquid needed to enable the material to flow across test strips. As a result, most antigen tests have a sensitivity of anywhere between
50% and 90%—in other words, one in two infected people might incorrectly be told they don’t have the virus. Last month, Spanish health authorities returned thousands of SARS-CoV-2 antigen tests to the Chinese firm Shengzhen Bioeasy Biotechnology after finding the tests correctly identified infected people only 30% of the time, according to a report by the Spanish newspaper El Pais.
www.sciencemag.org
And depends if machine can do testing in parallel or series as say 100 passengers x 12 minutes it'll take a quite a few hours to test em all or you turn up 24 hours in advance to check in and get tested - otherwise you'll likely need a few machines (cost?)