Few domestic airlines even offer actual meals anymore, and those that do usually offer a limited selection, and no longer cater to special diets because the possibility of waste if the flight is delayed, canceled or you are reaccomodated on an alternate flight or airline. But, call your airline just to make sure. The reservations agent should be able to let you know.
Still, even if they do offer a gluten free option, make sure you have enough food in the event that your order gets lost, or in any other way messed up, or you encounter a significant delay like Takala mentioned. I fly a lot (work for an airline), and while I have had my share of snags, most of the time I've had smooth sailing. The TSA will let you pass with just about anything if you tell them it is because of a gluten sensitivity. Really, they can be very accommodating.
Like Takala, I bring sliced cheese, rice crackers and fruit. I've also brought yoghurt (allowed past the TSA because of a special diet). A tip I received from a TSA agent for ANYONE wanting to bring yoghurt past security is to freeze it solid in its container, and keep it cold on the way to the airport. If its solid when you go through security, they can let it through. I've also never encountered grief from a flight attendant for bringing my meal on board. Just make sure you have a container small enough to fit under the seat in front of you and you're golden.
Remember, too, you can bring several 3 oz containers of liquid/gel substances in your carry on. I bring several small tupperware-type containers of peanut butter, then sliced apples or carrots to dip into it. I've also brought hummus in those same small containers, with sliced red peppers or other veggies or crackers to dip.
Honestly, I eat better than the passengers that buy a meal.
ETA: Funny, Julissa, about the gluten-free Lite I simply would not trust a gluten-free meal on an aircraft. Those meals are assembled in the same kitchens as all the other meals and I just would be too afraid of cross-contamination combined with a "please remain seated with your seatbelt securely fastened" situation.