Explainer: Why are airfares so expensive and when will they get cheaper?

As the global airline industry recovers from the Covid-19 pandemic and more people are flying, airfares are hitting significantly higher than pre-pandemic levels. Passengers are also finding it much more difficult to redeem reward points for flights on many airlines as availability shrinks and programme rules change. But why are airfares so high and what can people do to secure the best deals?