This has been touched upon in a couple of earlier comments but I feel I really must elaborate more. I am a nurse and I was fairly outraged at the inaccuracies of the diabetes story line in this movie. Firstly throughout the movie Baby-O is displaying hypoglycemic symptoms i.e. sweating, shaking, and feeling woozy. Theres symptoms would mean he needs glucose (sugar) not insulin. The first flaw with this is that hypoglycemia is typically caused in a patient with diabetes by taking too much insulin or in some cases over exertion or use of certain medications. None of these things seem to be present with Baby-o's situation. An injection of insulin in a person with hypoglycemia would cause the blood sugar to bottom out and send the person into a diabetic coma and eventual death.
It has been earlier hypothesized that Baby-o is a Type I diabetic because of his use of insulin but I do not believe this to be true. While it is a fact that many Type II diabetics do not need insulin shots it is by far not a rule. Many Type II diabetics do need insulin in addition to or instead of oral diabetes medications for a variety of reasons and the ones that need insulin are often the ones that appear to be a "normal" weight or in otherwise healthy condition. I make my judgment that he may in fact be a Type II diabetic because he is African American and the incidence of African Americans with Type I diabetes is relatively low (http://www.cdc.gov/diabetes/risk/age/youth.html), also the debated "snowball" scene in which he is shown to enjoy overly sweetened treats as even in the abcense of obesity African Americans who consume greater amounts of surgery foods and drinks have a much higher incidence of Type II diabetes than other racial groups, lastly hypoglycemia is more prevalent in those with Type II diabetes as opposed to Type I diabetics (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510957/).
It makes absolutely no sense that Baby-O would be freaking out about not having his insulin when he is not expected to be eating during the flight and he absolutely would not be assured of his own death as seen in the movie. He would probably start to worry once he began to experience symptoms of hypoglycemia but again would have no use for insulin and would probably be fine for a fairly extended period of time due to his Type II Diabetes which confers a greater resistance to negative symptoms of hypoglycemia (http://care.diabetesjournals.org/content/28/12/2948.full) before it became life threatening and if push came to shove he could eat a couple of hard candies and that would bring his blood glucose up enough to get him through until the plane landed at its final destination in South America or whatever Spanish speaking extradition free country they were going to.
Basically what I am saying is the entire premise of why Nicolas Cage has to stay on the plane to save his friend is 100% unnecessary and everything would have been fine for Baby-O if Cage would have exited the plane at Carson City like he originally intended to. In fact Baby-O would probably have been in a better state since he wouldn't have gotten shot by Cyrus the Virus. Unfortunately that would also ruin the greatest plane based movie all time and crush the hearts of both Jason and I.