I thank the authors for their efforts in addressing the comments made by the referees to the original manuscript. As mention in those reviews, the paper is well written and substantive. I include here a few additional comments and suggestions for the authors to consider:

P4 L5: perhaps not “novel”, “limited number of” since there have been several SUA aerosol measurement studies published (and a number more conducted) at this point as you note subsequently. A couple other examples would be Brady et al 2016 quadrotor OPC measurements, Telg et al 2017 fixed-wing with OPC and sunphotometer to study aerosol hygroscopicity

P4 L19: The sentence starting “Multirotor airframes” seems like it should be a separate paragraph, and “better” is goal-dependent—fixed-wing is certainly better for sampling over long distances and for longer times at altitude. You could restructure to state multirotors are better for the type of sampling you intend.

P6 L7: RCASS is briefly discussed here but not named. Could move the information in this paragraph to section 3.2 or introduce RCASS name here and then not have to define the acronym in 3.2. “The OPC is also a naturally” the “also” seems unnecessary here.

P6 L13: “there exist several benefits”

Table 1: Table captions go at the top of the table.

Figure 5: could add x, y, z axis indicator for clarity with discussion in 4.2

Figure 6 : a figure (or possibly panel in Fig 5) depicting the annular regions would be helpful

Figures 9 and 10: All text should go into the figure captions

Figure 10: capital N used in dN/dlog(Dp) elsewhere. Based on the axis labels, plots should be described as CAS vs SUA. It would be useful to color code the symbols by particle size

Section 5.1: a little more detail in the description of the SUA operation in PaCE would be helpful—what was the flight path (vertical/slant), how close horizontally were the SUA and CAPS for the comparison, altitude of SUA operations (RCASS data for comparison were in the altitude range 545-585 m (565 ± 20 m)? The statement “a common occurrence of low level (300 to 500 m or 0 to 100 m above the SUA operations site)” refers to cloud base? Was the SUA operation base at 400 m?

P13 L1: “fewer” particles, not “less”

P16 L25: “averaged range, this is represented” comma should be a semi-colon (since the clauses are independent) or make two sentences

I thank authors for their prompt and thorough response in considering and addressing the final comments I had on their revised manuscript. I am happy to advance the manuscript to publication.

Regards,

Troy Thornberry
AMT Associate Editor