Spirit Airlines is in talks with the White House over a potential bailout — a move that could test how far the Trump administration is willing to go to prop up a struggling private-sector company. Why it matters: A bailout would mark the latest in a series of increasingly aggressive examples of economic interventionism on the president's part. Catch up quick: Spirit — a budget airline that's been teetering on the edge of liquidation — is in advanced discussions to borrow up to $500 million from the government, according to a person familiar with the matter. The deal would likely provide equity warrants giving Uncle Sam a substantial ownership stake in the trouble business — possibly as much as 90%. "I guess it would be the Amtrak of the skies," Tad DeHaven, policy analyst at the Cato Institute, tells Axios. Follow the money: Trump has previously tied government intervention to stated policy goals — and to a financial return for the U.S. He procured a 10% stake in Intel for the U.S.…