(Adds details about CSeries order, updates sourcing, Delta comment)
PARIS, April 19 (Reuters) - European planemaker Airbus is close to a deal to sell 37 current-generation A321 passenger jets to Delta Air Lines, three people familiar with the matter said.
Such a deal would be worth $4.3 billion at list prices.
Airbus declined to comment. A Delta spokesman said "no decision has been made on any aircraft transaction."
If confirmed by the airline's board, which has the final say, the deal could be announced next week as part of a fleet renewal plan that may also include an order for 75 Bombardier CSeries jets and 50 options, the people said.
Both the CS100 and larger CS300 planes were part of the discussions, though the final mix of Bombardier planes is unclear, one of the sources said. The CS100 seats 108 passengers and the CS300 seats 130 in a standard dual-class configuration, according to Bombardier.
The Airbus part of the deal is for the current version of the A321, a 185-seat jet that has scored significant gains against the largest member of the competing Boeing 737 family.
Airbus has also seen a surge in demand for the newer A321neo, a costlier version with more efficient engines, but low oil prices have helped prolong interest in existing models.
Bloomberg News reported last week that Delta was poised to buy at least 30 Airbus jets.
The deal comes as Delta prepares to unveil the first of 45 A321 jets it has already ordered. It was delivered last month.
The airline, which has been reviewing part of its narrowbody fleet, plans to hold a media event and "fleet showcase" on April 28-29 at which it says it plans a series of announcements.
Boeing is also bidding for more of Delta's business, having recently agreed to sell it up to 20 used E-190 jets built by Brazilian manufacturer Embraer, market sources said.
Boeing reportedly took those aircraft as a trade-in with Air Canada in 2013, while Embraer is itself vying for part of Delta's latest fleet shake-up, the sources said. (Reporting by Tim Hepher, Alwyn Scott and Jeffrey Dastin; editing by John Stonestreet and Alan Crosby)