The "May Day" holiday is coming, and many people must be on their way home or traveling now.
Entering the airport 3 hours early, getting through security, and then sitting at the gate 1 hour early and watching the last boarding reminder rush past you?
It sounds counterintuitive: why would anyone risk missing a flight? But there's logic in it.
How far in advance is the best time to get to the airport?
First coined by the Nobel laureate economist George Stigler, this claim is now being made by mathematics professor Jordan Ellenberg in his book How Not to Make Mistakes: The Power of Mathematical Thinking.
Ehrenberg points out that the question of when to get to the airport is ultimately a question of "utility," a concept commonly used in economics to measure the benefits and costs of someone doing something. The benefits can be positive or negative: good things, like puppies and cakes, are positive for most people, while bad things, like illness or jury duty, are negative.
For some people, the benefits of not spending a lot of time at the airport are positive. At the same time, the benefits of not missing out on flights are also positive. So, Ehrenberg points out, when you can minimize the amount of time you spend at the airport and the chance of you missing your flight, then you should go to the airport at what time.
Time can really be "calculated"!
Ehrenberg expressed this concept mathematically. Assuming that the utility is denoted by "U", arriving at the airport 2 hours early means that 2 hours were wasted at the airport, hence subtracting 2U. But missing your flight means you'll have to spend more time waiting at the airport for the next flight, and saving 1 hour may end up taking 6 hours more, so you need to subtract 6U from your missed flight. In this way, Ehrenberg uses the formula to represent 3 different situations:
Scenario 1: Arrive 2 hours before departure with a 2% chance of missing a flight;
Scenario 2: Arrive 1.5 hours before departure and have a 5% chance of missing a flight;
Scenario 3: Arriving 1 hour before departure has a 15% chance of missing a flight.
By measuring time in U, you'll be able to figure out which scenario will give you the most utility. In scenario 1, the plane arrives 2 hours before departure, which is equivalent to 2 hours of waiting at the airport, so the utility is "-2U", but the probability of missing the flight is also factored into (-6Ud×2%=-0.12U). Adding up, the utility of Scenario 1 is "-2.12U". In the same way, the utility of Scenario 2 and Scenario 3 is "-1.8U" and "-1.9U", respectively. To sum up, from a mathematical point of view, it is most appropriate to arrive 1.5 hours before the flight takes off.
Of course, the above example equates the value of U to 1 hour. Maybe you can't bear it more than the average person, even one more minute at the airport will kill you, 60 seconds is 10U for you. Or maybe your biggest fear is missing your flight, and the thought of not being able to catch the plane – you can't even think about it, then a missed flight is 50U for you. These changes will affect the final calculated value and will also change the best time for you to arrive at the airport.
Is it possible not to waste time and not miss the plane?
"The best time is always between the two extremes," Erlenberg explains, "which also means that when you arrive at the airport at the best time, the odds of you missing your flight are not zero." ”
A probability of not being 0 means that as long as you take enough planes, there will come a time when you will miss a flight. If you're a frequent business traveler and haven't missed a single flight, chances are you've wasted too much time at the airport – and your utility has lost with that time.
In theory, this makes sense, but it doesn't answer the question of when exactly to go to the airport to minimize both the chance of missing a flight and the time wasted. The Transportation Security Administration (TSA) doesn't have a formal recommendation in this regard – there are many factors that can affect how long a traveler stays at the airport, but arriving at the airport 2 hours early is a rule of thumb for many frequent flyers.
Each airline has its own recommendations — Delta has compiled a brochure for travelers that lists the minimum time to arrive at the airport early for the most common U.S. domestic flights, and United and American Airlines offer similar services to travelers.
For those who want to try their luck, you can track the security wait times at each airport by applying for the TSA's pre-registration program, which allows background vetted and fingerprinted travelers to navigate the use of special security runways, or download the TSA's mobile app, which allows users to enter their wait time at the airport, creating a waiting time library.
Rush hour, a little earlier
Another way to calculate more specifically whether you won't miss the flight is to look at the time of your flight and see if the airport is particularly busy during that time. If you're traveling outside of "rush" hours, there's a good chance the airport will be less busy, meaning you can arrive a little late and won't be stuck in the queue for security and boarding.
So, when is the "rush" time at the airport?
LAX sets peak times for international flight arrivals, which is between 11 a.m. and 2 p.m. and 8 p.m. and 11 p.m. daily.
Continental Airlines recommends that passengers departing early arrive at the airport on Friday or Sunday evening and Monday morning, which translates to 6:30 a.m. to 9:30 a.m., 11:00 a.m. to 2:00 p.m., and 3:30 p.m. to 7:30 p.m.
So, if your flight departs at 3 p.m. on a Tuesday, you'd better arrive at the airport around 2 p.m. after the rush hour has passed, rather than arriving 2 hours earlier and ending up in a long line.
Perhaps, you'd rather spend your time at the airport
Then again, if you happen to be on opposite ends of the spectrum of what Ehrenberg is talking about—either you have a lot of time or you've already missed your flight—these airports might be the best fit for you.
Singapore's Changi Airport has an airport butterfly garden, an orchid garden with koi frolicking, and an open-air cactus garden and sunflower garden. Amsterdam Airport Schiphol in the Netherlands opened a library for travelers in 2010. Chubu Airport in Nagoya, Japan, has an airport hot spring, and the steaming bath is surrounded by large floor-to-ceiling windows, allowing passengers to soak in the hot tub and watch the planes take off and land.
编译来源：《史密森尼学会会刊》If You've Never Missed a Flight, You're Probably Wasting Your Time
But in the end, I still want to remind everyone that during the "May Day" period, travel is concentrated, and it is easy to affect the traffic time due to traffic jams and other reasons.
Reprinted from: Popular Science China