Hi, I flew to Spain recently from the UK. There were no issues with ballooning. I found loose clothing helped. I ate normally on the plane.
You can ask your consultant to send you a hidden disability lanyard that will help fast-track queues.
However, I did get stopped by security as my stoma bag showed red on the body scanner. I discreetly whispered to the guard that I have a stoma. I was then privately searched in a separate room. They did ask to see the stoma through the peep window of the bag, which I thought was a little unnecessary. They also asked me to flatten the bag by running my hand over it, which was not a problem as it was empty, but if it had outputted, I wouldn't have been pleased with this request.
Overall, flying was a positive experience. Hope you have a great time 👍


