Last month, American Airlines unveiled revamped F&B offerings that include a kale-and-romaine salad and lentil chili, at least in first class. At D.C.’s Reagan National Airport, the recently opened bar District features vegetarian fare such as a vegan quinoa burger. Keep your taste buds ready: It could be just a matter of months before dishes such as peach gazpacho and roasted cauliflower with black garlic land on mainstream menus.