Travelling on a bus for 15 minutes sitting next to a Sumo-Wrestler class obese passenger is bad enough. Yet siting next to an overweight pax for long-haul flight will be a nightmare. Even if you raise the arm-rest, half your seat will be taken up by the other pax.

In US, some airlines require these pax to buy 2 seats if travelling on Y class. What sort of policy does CX have on this? Also, what can I do, or how can I complain, if I encounter such situation?

Has anybody experienced this?