(CNN) Two former Health and Human Services secretaries told CNN on Wednesday that they mostly or exclusively flew commercial planes during their respective tenures, providing important context for the conduct of President Donald Trump's health secretary Tom Price, who is under fire for his use of a private jet for government business.

Mike Leavitt, who served as HHS secretary from 2005 to 2009 under President George W. Bush, told CNN in an email that "most" of his travel when he was in that role was on commercial jets, with rare exceptions.

"Most of my travel was commercial except for periods when we were dealing with health emergencies," Leavitt said.

Examples of when he did not fly commercial included, Leavitt said, "the period when we were dealing simultaneously with Katrina response, the breakdowns of the Medicare Part D (prescription drugs) implementation and an emerging pandemic threat where we were doing pandemic summits on each state."

In those instances, Leavitt said he used an aircraft already under lease to the Centers for Disease Control and Prevention or planes leased from other agencies, and that congressional approval was obtained to use the CDC plane.

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