Yes, I've seen the airport surge before, and I've also had pickups from both domestic and international (1 each) with zero waiting time. My first was domestic and I logged onto Uber app, but figured I'd eat at Maccas airport first. Pinged within 10 seconds of logon. Second time I was in the International waiting zone, within seconds of logon I got pinged for a international airport pickup. I've also received multiple pings for domestic pickup while in the international waiting zone, but I ignored those since it was a 10 minute drive to the pickup, and I was already very tired so needed to go home and rest.
I would guess it is a matter of knowing the peak airport times, with lots of international flights in the morning/evening but not so many during the day (what I've been told, no real ideas) and probably a similar thing for domestic, most movement in the morning/evening.
Probably need to do some analysis there, but we would need access to uber DB to do that properly. Next best thing is to see if the airport provides passenger movement numbers, eg, x,000 people between 6am and 8 am, 8am to 10am, etc...
Then you also need to factor in the source of those passengers, if they are a saturated uber market then more likely to be busy with uber, if not, then they would most likely use a taxi.