MEXICO CITY—Dozens of Mexico’s most dangerous prisoners, cuffed hand and foot, boarded army jets under heavy guard this year, a rogues’ gallery of cartel leaders responsible for smuggling tons of heroin, fentanyl, cocaine and methamphetamine to insatiable U.S. buyers.

The men were rousted from prisons, where money and corruption provided them with weapons, cocaine, booze, women and phones to run their lucrative underworld empires from behind bars, coordinating drug shipments as well as ordering killings and kidnappings, U.S. and Mexican officials said.

The prisoners had no idea of their destination.

“Welcome to America!” said Derek Maltz, interim head of the Drug Enforcement Administration when he greeted the first batch of prisoners as they disembarked nine months ago. A second group a

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