The scientific paper is well written and utilises an appropriate and well justified approach to modelling aircraft contrails, considering design factors which are often neglected in other studies. The comparison between methodologies (analytical + LES, RANS + LES) highlight the need for the current research with suitable conclusions drawn. Overall, the paper is structured and presented well.

A few points are highlighted for potential updates to the current and/or future work:

• Line 37 - an addition of a value to define soot-rich conditions? This would also make clear what constitutes soot-poor in the next sentence.

• The model references that the engine is representative of an UHBR turbofan, however the water vapour emissions used (and hence in effect, estimated fuel flow) are from an RB211. This is an older, much lower BPR engine. It does not take away from the results and modelling, but perhaps more representative boundary condition to an UHBR could be used within future work.
• Figure 2 could be reduced in size, and/or added alongside it, images of the mesh (and result of mesh adaption process) downstream could be shown to understand how refined RANS grids must be.  
• The water vapour and soot particle emission number could also be added in Table 1 for engine boundary conditions. This would allow for results to replicated and compared more accurately within the community. This would be beneficial whilst experimental measurements remain scarce.
• Line 329 - would assuming that all soot particles were activated not lead to smaller ice crystals, as more particles compete for the same water vapour?

A few technical corrections could also be addressed:

• In abstract/introduction, CO2 and NOx do not use subscripts. In 2.2 Microphysical Model, the chemical formulas do use subscripts. To be consistent, should CO2 and NOx use subscripts too? (i.e. CO₂, NO_X)
• Line 24 - can use ERF instead of 'effective radiative forcing' as acronym just introduced.
• Line 76 - Use of ‘us’ – ‘This allowed the full… …to be taken into account’ would be less ambiguous.
• Line 224 - Are these values defined within a table? (i.e. Tab. ??)
• Line 232 - Need to update table reference (Tab. ??)

see Supplement