Dear Editor-in Chief and authors,

Thank you for this invitation to review the manuscript by Russell-Jones D et al. entitled: “Flying with insulin treated Diabetes" submitted to the Diabetes, Obesity and Metabolism.

This is a review discussing the physiology and pathophysiology of glucose regulation and management of diabetes in the air allowing certain insulin treated pilots to fly

Major concerns
1.1. Among keywords, “Systematic review” is stated. This is not a systematic review.

1.2. Table 1 cannot be seen in full length. It may be the pdf file that somehow has cut the table into half.

1.3. According to the journal website, “the scope of the journal includes human pharmacokinetics and pharmacodynamics, cost-effectiveness studies, preclinical pharmacology, and phase I-IV clinical trials. High-quality meta-analyses and systematic reviews that provide original information on treatment effects and safety are also considered as original research papers”.

I do not find the manuscript to fit into the aim or scope of the journal. This is more or less a narrative review and may better be suited in another journal, e.g. Diabetic Medicine, Diabetes Metabolism Research and Review, or in a non-diabetes journal focusing on aviation.

Minor Concerns:
2.1 Page 3 line 21: A typo “regulation”

2.2 Page 4 line 12 A typo “There”

2.3. Could the authors provide information of altitude induced effects on CGM accuracy? It is well-known that pressure on the CGM can alter the CGM signal, the so-called PISA.

2.4. Are there any studies investigating whether high altitude affect hypoglycemia awareness?