I have had type 1 for over 10 years and fly 5 or 6 times each year.
I would never travel without my doctor's letter. However, I have only been asked to show it once and that was when there was heightened security. It was used to prove I had diabetes. Therefore, I do not think the lack of reference to NovoRapid is relevant (most airport security staff have no idea what a Lantus or NovoRapid looks like or does).
When I got a pump, my letter changed and I threw out my tatty old MDI letter so I can't tell you exactly what is said although there was a sentence mentioning "risk of death" if my kit was taken away. There was no mention of the types of insulin or number of vials.
FYI my current letter states
"This letter is to confirm that the above person has Insulin Dependent Diabetes requiring insulin continuously through a subcutaneous pump device. It is therefore essential that she carries this at all times along with insulin, cannulas, cartridges, needles and other medical equipment as part of her treatment.
"The pump manufacturer stipulates that the insulin pump should not be exposed to x-ray equipment, advising instead a "walk through" or hand wand is requested."
