Delta Air Lines is introducing a premium economy section on long-haul international flights this summer as part of an on-going $2 billion upgrade programme.

“Economy Comfort” will include new seats with up to four additional inches of legroom and 50 percent more recline than the carrier’s standard international economy class seats.

Set to be installed in the first few rows of the economy cabin on more than 160 Boeing planes, the new seat is similar to a product currently provided by Air France-KLM, Delta’s joint venture partner.

It will be similar to upgraded economy services available on flights operated by Delta joint venture partner Air France-KLM.

Passengers who have purchased an international economy ticket will be able to upgrade to Economy Comfort seats for an additional fee of between $80 and $160 one-way.

Those opting for the service will also have early boarding and free spirits throughout the flight. The benefits are in addition to standard international economy class amenities, including complimentary meals, beer, wine, entertainment, blankets and pillows.

In-seat power will be available on aircraft equipped with personal entertainment systems which come with free HBO programmes and other content.

Glen Hauenstein, the US carrier’s executive vice president of marketing and network planning, said that the company decided to offer the economy enhancements following previous investments in its business class service.

“Economy Comfort is one of many elements Delta is committed to delivering to our customers as part of a more than $2bn investment we are making in the air and on the ground to improve the customer experience and position Delta as a leader in customer service.”

The airline also plans to install 34 horizontal flat-bed BusinessElite seats with direct aisle access in each of its 32 Airbus A330s by 2013. 

This will enable Delta to offer full flat-bed seating in BusinessElite on all international wide-body flights, representing more than 150 aircraft.