These travel tips from MedHelp.org and the Sugar Sense app might be helpful, too.
http://www.medhelp.org/diabetes/articles/Travel-Smart-with-Diabetes/1709
It's wise to get a letter from your doctor or diabetic nurse specialist that explains you are diabetic and prescribed insulin. In the UK you can ask for a "diabetic card" that helps explain it too, should someone find you unconscious or confused. The letter from your GP should also explain that you require to have your syringe-pen, needles, monitor and maybe other medications with you at all times when traveling on an aircraft. While I have never had an issue, I do this as a matter of routine, just in case. Most airlines and border controls are very experienced and appreciate what diabetics need to have with them - and most airlines are equally prepared for diabetic passengers. I think it does depend much on the countries you may be traveling to, so I prefer to be prepared for any issues rather than risk a problem.
Tony