1/Earlier, I anecdotally said that aircraft were flying higher because 10% load factors mean the optimum altitudes increase. That thread's here: https://twitter.com/ethanklapper/status/1248647269517275138

2/Now, I quantified and statistically tested this hypothesis that aircraft are flying higher.

And they are, quite a bit.

3/I took daily ADS-B snapshots of all of Houston Center (ZHU) for all passenger air carrier aircraft in level flight above FL300.

Two groups, with daily averages used: 2/12-3/11, 3/12-4/9

4/In the first group (2/12-3/11), aircraft were flying at an average of 35,640 ft pressure alt.

In the second group (3/12-4/9), aircraft were flying at an average of 37,625 ft pressure alt.

That's a 2,175 ft difference, or in RVSM vertical separation standards, 2 flight levels.

5/I ran an unpaired t-test to test for significance on these means.

This was VERY significant, p < .001.

So at least in this uncontrolled test, aircraft are flying statistically significant higher with lighter loads.

Thanks for coming to my Ted Talk.

IN SUM: Passenger aircraft are flying 2,000 feet higher on average in the past month compared to the month before due to lighter loads. Lighter loads means higher optimum altitude for best specific range.