Delta Airlines debuted an overhauled fare structure that will change the way travelers book flights, earn miles and qualify for free upgrades. In total, Delta fliers will see as many as 11 fare options to choose between on some flights.

From new fare categories to enhanced booking flexibility, here's what Delta's latest move means for travelers.

Delta says a passenger's Medallion status and the type of seat they purchased remain the most important factors when determining upgrade eligibility. If two passengers have equal status and one has purchased the Classic seat, while the other paid for the Extra, the one who purchased the "Extra" seat would receive the upgrade.