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  • Tim Donohue

NYC Marathon inbound travel - first look

We're excited to issue our first disruption outlook, especially because it's relatively favorable! As we build our deep learning algorithms, these forecasts will evolve into a more predictive product - in the meantime, we believe we can still deliver some useful insights.


Our first outlook focuses on travel inbound to the NYC airports (EWR, JFK, LGA) for Thursday, November 4 and Friday, November 5 ahead of the Sunday marathon. Broadly, high pressure builds in on Thursday behind a weak cold frontal passage Wednesday afternoon. High pressure remains in control for Friday, though an area of low pressure offshore may deliver a glancing impact. As an aside, here's a good explainer from the National Weather Service on high versus low pressure systems (tl;dr high pressure generally promotes fair weather while clouds and precipitation are associated with low pressure). In terms of sensible weather, clouds will be on the increase through the day on Thursday, however any rain should hold off until Thursday evening. Thursday night will hardly be a washout, with rain probabilities no higher than 1 in 5, though the chance for a stray shower lingers into Friday afternoon.


So what does this mean for airport capacity - and, in turn, potential delays? If you want a primer on the concept of airport capacity and what variables influence it, we'd encourage you to check out our blog post on the topic. Any periods of rain may result in conditions that are marginal for an airport to maintain its optimal arrival rate, though a drastic reduction in capacity is not expected. The other question as it relates to airport capacity is airport configuration and this particular answer is complicated by the fact that we're examining NYC airspace. Given the proximity of EWR, JFK and LGA (plus a number of satellite airports), the direction air traffic flows at one airport can create a conflict for another. Relatively light forecasted wind speeds also add some ambiguity to this exercise. All that said, we'd bet EWR and LGA deliver no worse than a 38 arrival rate; JFK is a slightly more complicated case, though we don't anticipate rates lower than 42.


With a grasp on what to expect on the supply side (i.e. airport capacity), let's turn our attention to the demand side (i.e. schedule activity). The NYC marathon occurs at an interesting juncture for flight schedules, as the the slot usage waiver previously providing relief for domestic operations at all three NYC airports expired on October 31, 2021. This resulted in a 26% increase in flying week-over-week. The airports unsurprisingly have suffered a bit of indigestion as a result of this, with 22% of flights into NYC airports arriving at least 15 minutes late in the last two days (up about 5 percentage points from the previous 30 days).


There are a few potential demand overages to call out at the hourly level, most of which occur at EWR (this will, no doubt, be a recurring theme in these outlooks). Headed into late Thursday afternoon at EWR, demand is between 40 and 44 scheduled arrivals in the 4, 5, 7 and 8 p.m. hours: this becomes problematic if some rain materializes to lower the arrival rate to 38. We highlight these instances of demand overages because they essentially result in queues to land. This queueing can take place in the air, when an arrival may be made to circle or take a seemingly wandering route, or take place on the ground at the arrival's origin station, where the arrival is given a "wheels up time." Regardless of where arrivals are made to queue, queueing produces delays (though arrivals that have not yet taken off can absorb much longer delays). It's also worth noting there's excess supply in the 6 p.m. hour, which affords some room to catch up. The only non-weather related delays we'll speculate on sadly owe to the Thursday Night Football game featuring the New York Jets (no pun intended). While we admittedly won't be able verify this suspicion, we'd wager that airlines will have to work through an uptick in agent sick calls: this shouldn't cause the wheels to come off, but perhaps some perceptible sluggishness.


Where does that leave marathon runners flying in on Thursday or Friday? We'll be back tomorrow with an updated weather forecast and some predicted delays, but we don't anticipate an extraordinary level of disruption. Runners (or supporters) flying into JFK or LGA should experience almost zero air traffic delays (delays on account of airline staffing, aircraft servicing, network effects, etc. are of course possible); runners flying into EWR may experience minor delays if arriving later Thursday. We don't think this forecast calls for rebooking (perhaps adjusting some delay expectations) but we're also not subjecting ourselves to the stress of running a marathon. If you're scheduled to arrive EWR later in the day on Thursday and anxious about minor delays, the goods news is airlines are progressively offering some rebooking flexibility. Airlines have eliminated change fees for most tickets, though a fare difference may still apply; additionally standby is increasingly free. Same-day confirmed change (SDC) policies are a bit too varied to generalize, so we've linked to respective policies for Alaska, American, Delta, JetBlue, Southwest and United.


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