Comfort+ is an enhanced version of the seats Delta previously called Economy Comfort. Up until now, travelers would get the option by choosing a Comfort+ seat during the seat selection process and then paying for the upgrade.
Elite members of Delta's SkyMiles frequent flier program -- Delta's most loyal customers -- had been able to get free upgrades to the Comfort+ extra-legroom seats, which come with free wine and beer, free movies, dedicated space in overhead bins and priority boarding.
But Delta is increasingly looking for ways to encourage customers to pay extra for perqs rather than giving them as complimentary benefits. Some of those efforts include aggressive "upsell" messages during the online booking process.
The Comfort+ fares may make it more likely that travelers will choose a higher-priced fare for the perqs. And for elite frequent fliers, it means there may be fewer seats available for free upgrades.
Delta also plans in the next several years to install dividers between the main cabin and Comfort+ and first class to emphasize the difference between the offerings.
For international flights, Delta will still offer the Comfort+ seats as an upgrade.