Nowadays there are many airlines offering gluten free, vegetarian or vegan food. It is enough to place your order for special food in advance, preferably 48 hours ahead. We tried it and remained very pleased. It certainly wasn’t the best food we’ve ever eaten, but it was edible. Below find the list of airlines that offer food for people with special needs:

https://www.alternativeairlines.com/gluten-free-airline-food