I traveled to and from Europe aboard Air France, and I requested vegan meals. As long as you notify them 48 hours in advance, most airlines offering food will accommodate vegetarian and vegan meals. They were not bad, and one of the perks is that when you order a special meal you get served first, and everyone around you has to hungrily watch and smell and consider as you eat and explain reassuringly "I ordered the vegan meal - that's why I'm getting treated special." And then, when they get their gross meat dish, they always say "I wish I had ordered that."
These are the vegan meals they offered me:
Curried Rice with peas and mushrooms and a shredded root salad with black olive tofu. For dessert: Applesauce, and Chocolate Almond Cake