  Actual airborne time (AAT) is the time between wheels-off and wheels-on of a
flight. Understanding the behavior of AAT is increasingly important given the
ever growing demand for air travel and flight delays becoming more rampant. As
no research on AAT exists, this paper performs the first empirical analysis of
AAT behavior, comparatively for the U.S. and China. The focus is on how AAT is
affected by scheduled block time (SBT), origin-destination (OD) distance, and
the possible pressure to reduce AAT from other parts of flight operations.
Multiple econometric models are developed. The estimation results show that in
both countries AAT is highly correlated with SBT and OD distance. Flights in
the U.S. are faster than in China. On the other hand, facing ground delay prior
to takeoff, a flight has limited capability to speed up. The pressure from
short turnaround time after landing to reduce AAT is immaterial. Sensitivity
analysis of AAT to flight length and aircraft utilization is further conducted.
Given the more abundant airspace, flexible routing networks, and efficient ATFM
procedures, a counterfactual that the AAT behavior in the U.S. were adopted in
China is examined. We find that by doing so significant efficiency gains could
be achieved in the Chinese air traffic system. On average, 11.8 minutes of AAT
per flight would be saved, coming from both reduction in SBT and reduction in
AAT relative to the new SBT. Systemwide fuel saving would amount to over 300
million gallons with direct airline operating cost saving of nearly $1.3
billion nationwide in 2016.
