The President said he's "not happy" with Price over those flights and told reporters that he'll "look at it".
"I have no idea who came up with this notion and where it came from, and the notion you could spend $400,000 in what, five months, is stunning", Sebelius said.
Politico first reported Price's use of charter jets for official business earlier this month, and followed that article with another that said the secretary has traveled on charter flights at least 24 times since May, citing people familiar with his travel plans and a review of HHS documents.
"On September 19th, Politico reported that you had chartered a private jet on several short official trips, including a $25,000 private flight from Washington, D.C.to Philadelphia and back - a trip that would at most cost $725 round-trip on a commercial airline", the letter reads.
The president did not elaborate on whether he would dismiss Price or what consequences, if any, Price would face, but promised he would "look at it".
Other members of the Cabinet contacted by The Associated Press last week said they personally foot the bill for chartered travel or reimburse taxpayers the difference between commercial and chartered travel.
Lawmakers are demanding information on political appointees' use of government planes for personal travel, as well as their use of private charters for official travel.
Inside the department, the mood is souring. She also confirmed that the use of private planes had been suspended.
Two current officials this source spoke to simply could not "believe he was using taxpayer money for a private plane".
Price is facing two investigations into his use of private jets amid Republicans' failed attempt to repeal the Affordable Care Act.
In a letter Tuesday, House investigators asked Price and more than 20 other agency heads to list all use of private, charter aircraft and use of government-owned aircraft by political employees since Trump's inauguration.
Trump's remarks were the latest example of the White House distancing itself from Price's actions.
Democrats, meanwhile, are more forthcoming with their outrage. "Not everybody can lease a plane like that and fly around the country".