As investments, airlines are best left to relentless optimists and colourful egomaniacs. Over the long term, a diversified portfolio of airline stocks has reliably lagged behind broader market averages. Airlines’ long-run operating margins have averaged just 2 per cent since 1950, says UBS.

Singapore Airlines, which reported third-quarter numbers on Tuesday, is one of the less terrible operators. It has the two qualities every carrier needs to withstand troughs: a strong brand and a patient majority shareholder (state-owned Temasek, in SIA’s case). On top of that, it has one of the world’s better-looking balance sheets: cash in the bank exceeds long-term liabilities by more than three to one; a youngish fleet of fuel-efficient aircraft; and one of the most highly rated management teams around. As such, the world’s largest airline by market capitalisation is an industry benchmark. If SIA is struggling, pity the rest.