[Delta's record revenue](https://www.marketwatch.com/story/delta-reports-record-revenue-and-a-profit-beat-even-as-fuel-costs-surge-b1e33336?mod=mw_rss_topstories) is actually a trap — fuel costs surged to their highest quarterly level ever, which means the airline had to work twice as hard just to beat profit expectations. That's the inverse of operating leverage.

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