Virgin Atlantic is being urged to serve only vegan meals on board, in a bid to ' offset some of the environmental damage caused by flying'.
The letter outlines how the 'United Nations states that a global transition to vegan eating is urgently needed to combat the worst effects of the climate crisis'.
'More clean, less mean'
"Virgin Atlantic has an opportunity to lead the way towards a more clean, more green, and entirely less mean future," PETA Director of International Programmes Mimi Bekhechi wrote in the letter.
"Serving only vegan food on Virgin Atlantic flights would let the world know you're serious about tackling the biggest problem civilization has ever faced. For our planet and all the sentient beings we share it with, this move can't come soon enough."
PETA adds that animal agriculture is a 'major contributor to climate change, and causes deforestation, drought, desertification, species extinction, and the devastation of ecosystems on a massive scale'.