Airlines make money when their aircraft are moving, especially in the air. But it turns out that a significant amount of airline time is spent on the ground.
We looked at the 24-month period from January 2015 through December 2016. The chart below shows the findings. On the left, we see the amount of time US airlines report being on the ground (taxi in and out) compared to in the air.
The data is remarkably consistent. The average flight including taxi and air time is 138.6 minutes.  Flights have started to take slightly more time – in January 2015 the average flight was 136.5 minutes, but by December 2016 it was 144.4 minutes. On the chart to the right, we see the taxi time component is typically 17% of total flight time. One-sixth of any given flight is spent on the ground!
What does taxi time look like? The following chart shows the breakdown between taxi out (gate departure) and taxi in (gate arrival). We observe that these times are also remarkably consistent. The average flight must contend with 24 minutes of combined taxi time.
We have previously noted that a typical airline operational minute is worth $150. Next Gen navigation promises to cut time from each flight – in the air. But airports, most of which seem to be under continual construction, have offered very little in the way of time savings.
If on average airlines could save one minute every flight, the savings value would be enormous. In the next table, we show daily flights from December 2016 for reporting US airlines:
For US carriers, the value of a single operational minute represents substantial savings over just one month. Imagine the savings over a year?