Airplanes do not typically serve gluten-free meals. All meals for a flight are produced in mass well in advance, and requesting a gluten-free meal during the flight will not yield much favorable results. A gluten-free meal must be arranged well in advance, many airlines will do their best to accommodate your dietary requests if you follow their policy, but expect to give at least three days advance notice.
Airlines are familiar with providing Kosher and vegetarian options and the gluten-free request is becoming more popular; as long as your request is in place with plenty of time, your chances of getting a safe meal are pretty high. However, always have a backup plan in case your request didn’t get communicated properly and you’re left flying without anything to eat. As always, make sure you have some gluten-free snacks with you.
Map out the legs of your trip with all stops, request your meals accordingly, and bring enough snacks to either augment your meal or serve as a replacement in case of a mistake with the airline arrangements. Remember that it is common to underestimate your hunger when traveling and you may not bring enough food with you to get you through the trip. Bringing more than you think you’ll need is wise.