Originally Posted by
usbhub
I know the case of the flights across the Atlantic (Air France and KLM). The passengers are obliged to buy round-trip tickets (a one-way has an enormous cost). No refund is possible if you do not come back (which is often my case) because the return ticket is just $2! I noticed also that the planes are always full. So, it is essential for big planes to have all seats occupied.
I'm afraid someone's been telling you porky pies. No refund is possible because you most likely bought a nonrefundable ticket (you wouldn't get a refund if you cancelled before departure either - although you could probably rebook for a fee, which you can do even if you've flown half the ticket) - but the actual fare construction is such that each half is generally half of the ticket cost. The real problem you'd face is that you agreed to fly the itinerary as ticketed, and the airline very likely has the right to charge you more money for the pleasure of not taking your return journey. They mostly don't, but they could. The real reason for these expensive one-ways is that the business travellers who are the primary audience for one-ways have the spare cash to buy such tickets, but they don't want to make them convenient for the cheap passengers who fill the back.