I'd never heard of skiplagging before but I'm really struggling to see what the problem is. From how the article describes it, a traveller buys a ticket and pays the full requested price, but simply opts not to travel one leg that they'd already paid for. The full price was paid either way, but now the airline saves money on fuel by carrying less weight. Where exactly are they claiming they lose money? Just because someone chose a cheaper flight? Utter bullshit.