Saturday’s Spirit Airlines shutdown is entirely on the Biden administration — and more specifically, on the faux-populism of its Federal Trade Commission chief, Lina Khan. On top of all the travelers left scrambling, 17,000 Americans just lost their jobs, while future travelers will have one less choice and the rest of the industry faces reduced competition. No, Spirit’s bare-bones approach wasn’t for everybody (paying for every checked bag rubs many the wrong way), and perhaps the business was