Delta upgrades are not free for the general public, but they are a complimentary benefit for Medallion Elite members and certain top-tier credit card holders. If you hold Silver, Gold, Platinum, or Diamond status, you (and one companion) are eligible for "Unlimited Complimentary Upgrades" to First Class and Delta Comfort+ on most domestic and short-haul international routes. For everyone else, upgrades must be "paid" using either cash or SkyMiles through the Delta app or at the gate. As of 2026, even Basic Economy tickets are ineligible for upgrades, regardless of your status. If you are not a frequent flyer, your best chance for a "free" move is a "complimentary operational upgrade" if the economy cabin is oversold, but this is a rare occurrence that usually goes to those with some level of status first.