Delta Air Lines
Delta awards million-miler status based on total Medallion Qualifying Miles (MQMs) earned during a SkyMiles member's lifetime. Unlike American, purchasing higher-priced tickets that earn bonus MQMs will get you to lifetime status faster.
After achieving one million miles, Delta provides frequent-fliers with lifetime Silver Medallion status. Perks of Silver status include priority check-in, priority boarding, unlimited complimentary upgrades and 25 percent bonus miles on every flight.
At two million miles, SkyMiles members earn lifetime Gold Medallion status. Additional Gold benefits above Silver-level perks include complimentary Economy Comfort (enhanced legroom) seats on domestic flights, fee waivers and 100 percent bonus miles on every flight.
At four million miles, SkyMiles members earn lifetime Platinum Medallion status. The additional Platinum benefits above Gold-level perks include complimentary Economy Comfort seats on international flights, higher priority for upgrades and additional fee waivers.
Delta also provides a selection of gifts from Tumi, Tiffany and Co., or Hartmann to its million-mile fliers.
American awards million-miler status based on actual flight miles flown on American or any AAdvantage frequent-flier program partner airline. Bonus flight miles for certain higher-priced tickets such as first- and business-class aren't included in the calculation.
After achieving one million flown miles, American provides frequent-fliers with lifetime AAdvantage Gold status and 35,000 bonus miles. Perks of Gold status include priority check-in, security and boarding, as well as complimentary access to preferred seats in coach—those near the front of the cabin and enhanced legroom seats—and 25 percent bonus miles on every flight. (Read more: American Luring Frustrated United Fliers With Status Match)
At two million flown miles, AAdvantage members earn lifetime Platinum status along with four one-way systemwide upgrades that can be used for first- or business-class travel. Additional Platinum benefits above Gold-level perks include priority baggage delivery, oneworld lounge access when traveling internationally and 100 percent bonus miles on every flight.
At each additional million-mile mark, AAdvantage members receive four more one-way systemwide upgrades.