Airlines are extremely worried about the decline in demand for first class tickets. But they only have themselves to blame.

The industry has disrupted itself, says Geoffrey Weston, a partner with Bain & Company. On short-haul flights, a lower-cost model has won. Most passengers on these routes who would typically have purchased first-class tickets are now sitting in seats with similar legroom to economy, only with an empty middle seat. They instead make do with extras such as lounge access, food and drink to keep costs down.