> Airports have everything from huge IoT systems managing the climate of the terminals, thousands of monitors for public information, controls for automated baggage handling, traffic/parking management sensors, vast sewer systems with sensors to manage storm/sanitary/glycol recovery/water, security systems (tens of thousands of cameras/doors being monitored), and then hundreds of smaller systems doing everything from managing ground transportation through to emergency dispatch. … I'm not sure it's even feasible to air gap all of that - the loss of productivity and additional cost would be far greater than the perceived security risks.
Which of those systems would suffer from decreased productivity were they disconnected from the Internet? Indeed, I imagine that they'd experience increased productivity: there's no need for an air conditioning system to get its updates over the Internet rather than, say, by a human being with a thumb drive. Ditto monitors, ditto baggage handling, &c.
Many of these systems have a management UI available through mobile devices because of the need for staff to manage them while in the field or out of the office. As I said, some of the most critical systems are air gapped but there are critical systems that require an internet connection for practical use.
Emergency dispatch for example - the airport acts as a PSAP (https://en.wikipedia.org/wiki/Public-safety_answering_point) and requires integration into regional systems. They have radio backups but my understanding is that they pull a lot of data via the internet. The first responders also have cloud apps that help them route to a location or see the position of other nearby resources.
There is also considerable coordination with regional/national infrastructure owned by the airlines for managing when aircraft will depart/arrive. That would be much harder without an internet connection.
The airport will continue to operate safely if they lose internet connected infrastructure but the efficiency will drop quickly and the national airspace is like a busy road network - congestion in one area can rapidly cascade and cause chaos.
Which of those systems would suffer from decreased productivity were they disconnected from the Internet? Indeed, I imagine that they'd experience increased productivity: there's no need for an air conditioning system to get its updates over the Internet rather than, say, by a human being with a thumb drive. Ditto monitors, ditto baggage handling, &c.