Now that forecasts predict tourism won't fully recover until 2023, these transit centers are getting a rare, low-traffic chance to make many of the changes flyers have long wanted—along with upgrades they never imagined.

Among them: disinfection booths, biometric security scans, automated customs and border patrol screenings, and enhanced self-check-in stations. Together, they represent the most significant overhaul of the airport experience since Sept. 11.

"The traditional way we design airports has long been hamstrung in two directions," says Matthew Johnson, who helped spearhead the ongoing $14 billion renovation of LAX in Los Angeles as an aviation principal for architecture firm Gensler.