Delta Air Lines Inc. is building a computer system to let travel agents book flights directly with the carrier, helping trim the $300 million spent annually on fare distributors such as Sabre Holdings Corp.

Fare data and ancillary services such as seat selection and paying checked-bag fees will be available to agents when the system goes live in the fourth quarter, said Trebor Banstetter, an airline spokesman. Delta hired Farelogix Inc. on April 12 to do the work, Banstetter said.

Airlines pay so-called global distribution systems as much as $5 a flight segment to collect and share fares and data with travel agents. American Airlines parent AMR Corp. used Farelogix to build a proprietary system for travel agents, and is involved in legal battles with Sabre and Travelport Ltd. over the issue.

Delta has said it pays Sabre, Travelport and Amadeus IT Holding SA about $300 million a year to distribute fare and flight data. Including payments to online travel agencies such as Travelocity, which is owned by Sabre, such spending totals $400 million a year, Chief Executive Officer Richard Anderson said on a Jan. 18 conference call.

Farelogix’s system for American will be “repeatable from a technology point of view” for Delta and other airlines and won’t have to be created from scratch, CEO Jim Davidson said in a telephone interview.

Farelogix helps airlines use historical data on customer preferences to tailor deals and services such as day passes to airport lounges and which specific seats they like on planes, Davidson said.