PARIS, Oct 29 (Reuters) - Airbus is in the

process of finalising delivery of its longest-range single-aisle

jet, the A321XLR, to Spanish airline Iberia, industry sources

said on Tuesday.

The keenly awaited delivery - the first of a new variant of

the best-selling A321 jet - involves a formal handover and

transfer of ownership, though the Spanish airline will not

officially welcome the plane into its fleet until next month.

The plane is scheduled to depart Hamburg, Germany, where it

was assembled, for Madrid at 1500 GMT on Wednesday, just ahead

of Airbus' quarterly earnings announcement, according to

departure information posted by FlightRadar24.

An Airbus spokesperson declined comment.

Iberia did not immediately respond to a request for comment,

but its parent IAG, which also owns British Airways,

said the Spanish airline would hold a ceremony to mark the

delivery on Nov. 6.

The delivery, originally due in 2023, will revive industry

attention towards a hotly contested part of the market between

Airbus and Boeing ( BA ).

Launched in 2019 to steal a march on Boeing's ( BA ) plans at the

time to build a new jet in the middle of the market, the A321XLR

targets a gap left by the out-of-production Boeing 757, where

the A321 family outsells the largest versions of the 737 MAX.

The delivery also exemplifies pressure on Boeing ( BA ) to

obtain certification for the largest member of its single-aisle

family, the 737 MAX 10, delayed by an issue with an anti-ice

system. Boeing ( BA ) has said certification timing is a matter for

regulators.

The A321XLR is designed to carry out missions previously

reserved for wide-body jets, allowing airlines like Iberia to

fly deeper into Europe from the United States, for example,

without the commercial risk of having to fill a larger plane.

Its design called for a novel type of rear central fuel

tank, moulded into the contours of the fuselage, to eke out more

space for fuel and extend the range.

But the design raised concerns among regulators about

the risk of fire and evacuation times in the event of an

accident, prompting changes before it could be certified.

Airbus has said it has sold more than 500 A321XLR jets

but does not separate them out from orders for the A321 family.

Boeing ( BA ) has argued the XLR addresses only a small portion of

the market for single-aisle jets, the busiest part of the

industry, which it pegs at 33,380 aircraft over 20 years.