Several comments have not been (fully) addressed. Please take the opportunity the reviewers gave you to improve all aspects of your manuscript.

From reviewer 1:
the answer below does not address NO3:

"Page 34043, L15: how are aviation NO3 emissions estimated. Do you have mass and
number emissions for all aviation aerosols? Please describe in more detail."

The now extended description of the emission setup (see reply to the first comment
above) should address this comment. An additional sentence has been added in
Sect. 2 to further clarify that number emissions are estimated from the mass of emitted
BC and primary SO4: “Namely, we have used the same size distribution parameters
as for the reference case in R13 and applied them to both emitted primary aerosol
species, i.e. BC and primary SO4, in order to derive number emissions from mass.”

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Reviewer 2:

You missed the opportunity to point out to RCP2.6 rather akward behaviour in terms of BC. The trend in BC emission (and to as lesser extent of SO2) from RCP 2.6 that the reviewer refers to should be indicated in your text.

"Secondly, the description of the aviation emissions from the RCPs is only done
partially. It would be nice to have a more specific description of the data used for the aviation emission (e.g. assumption made for traffic growth, fuel efficiency) especially the ones coming from the RCP2.6. For example, the huge increase (2000-2030) for BC in RCP2.6 would need more explanations."

"The RCPs are general-purpose scenarios covering all sectors and they were not
specifically designed for aviation. Therefore, they do not follow the standard methods used in other transport scenarios (e.g., QUANTIFY). As we state in Sect. 2, they are mostly based on (or rescaled from) existing scenarios, often following very basic assumptions. Despite their limitations concerning the short-lived species (see, e.g., Takemura 2012), our main motivation for using the RCPs was that they were specifically designed for the IPCC and a large number of single- and multi-model studies are based on them. "

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Reviewer 3:

try to sharpen your answer of the following comment:

page 34044, line 23-24: “it should be questioned whether the assumptions of high
aviation emission shares in RCP2.6 are realistic RCP2.6 is unrealistically high”: This is the point. Is there really a good reason why they were constructed this way? Then you need to explain it."

"As we said in our first reply above, we now clearly state that RCP2.6 and RCP6.0
are based on questionable assumpions and therefore the corresponding results shall
be interpreted with care. Since we were not responsible for the construction of these
scenario, we can not explain the reasons behind these assumpions, but just report
the information available in the literature, as we did in Sect. 2. We believe that
RCP4.5 and RCP8.5 are reliable scenarios, since they are based on the QUANTIFY
scenarios and are also used in a similar study on future impacts of aviation (Chen and Gettelman, 2016). As mentioned above, for completeness and for consistencies with the companion paper (R15) we wish to show the results for all RCPs, but we do point out inconsistencies where appropriate."

Sincerely

Yves Balkanski

Thank you for the precisions brought by your answers.

Yves Balkanski