| MiniMed pumps don't set off metal detectors. I have heard that some other pumps will set them off.
Flying internationally is a bit more complicated than flying domestic. Usually, flying from the US to another country is no problem, but flying back into the US the restrictions are a bit tighter. Flying within the US is a piece of cake.
Take your supplies on board with you. I have never had my pump set off a metal detector, but it has been seen sticking out from my clothes. I have been asked about it, but have never been asked to take it off. You really don't need to carry anything to cool your insulin, but if you prefer, you can carry a gel pack. Coming back into the US be prepared to toss it. Your insulin will stay plenty cool on the flight back.
Have a note if you are concerned. I have only been asked once for a doctors note and it really was given a cursory glance. Keep your insulin in the original box with your Rx label still attached.
Honestly, there is little to worry about. I have never had my hand luggage searched in all of the years of travel except in South Africa.
Have a great time. | 
