I was led to believe it was an agent working for the player who arranged the flight. The agent Willie McKay and his son Mark organised(Willies other son is a Cardiff player)
Maybe they should refuse to pay, then maybe fifa should take sanctions against them, then maybe we could evict them out of our league and then maybe we could see them go bust and fold.
It seems that Willie McKay's son Mark was the agent acting for Nantes, according to this article. Guess the idea is that he would go out and find the best possible buyer. https://www.bbc.com/sport/football/47013474
He had been delivered though. He’d already been to Cardiff and signed a contract, he then returned to Nantes to say farewell. The issue then unfortunately becomes who Cardiff can blame and recover their losses from. I suspect Cardiff will pay the transfer fee as UEFA will ensure they do but then look to reclaim losses from the agent and airline who arranged the travel