I was recently on an Swiss Air flight, and requested a vegan option for my meal (using the option on the booking form). When the stewardess came round, she told me that they didn’t provide requested food for Economy Class!
So I guess you’re only allowed to be vegan if you fly First Class? 
She then looked puzzled and said:
“You don’t eat meat? And you don’t eat cheese? So… you just eat bread?” 
Ohhh if that was me I would have gone soooo mad and demanded a first class seat - then complained to her manager (do they have managers?!) that she was disrespectful of my beliefs…but thats just me…I love to complain 
I was once in the airline who to my request answered- the option is eat or not to eat.
Food is actually very philosophical question indeed.
That’s terrible! It’s such a shame that on most international flights you have to request a veggie or vegan meal. Why don’t they just make it one of the options.
Once I was on a long haul flight with no food choice (only meat or chicken options) and the lady next to me offered me her fuit cup.
I don’t know if you drink coffee but have you tried SoyGo? I always take it with me when I travel. Airlines never have soymilk options 
To be fair - they are offering a vegan option on long flights now.