FILE PHOTO: JetBlue Airways logo is displayed on a monitor in Terminal 5 at John F. Kennedy International Airport during a terminal test in New York August 23, 2008. REUTERS/Joshua Lott

NEW YORK (Reuters) - JetBlue Airways Corp JBLU.O said it was postponing delivery of 13 aircraft scheduled for 2019 and 2020, and had swapped its 2018 Airbus order of A321neos to 11 A321ceos, which have an earlier engine design.

In its first quarter earnings call, JetBlue said it was deferring eight aircraft from 2019 to 2023 and five aircraft from 2020 to 2024.

Deliveries of Pratt & Whitney engines have been disrupted by various technical problems, forcing Airbus to replace some A320neo jets with the earlier model to keep production lines flowing smoothly. It has made extra copies of the earlier type available for airlines that want them.

Differences in fuel performance are less obvious when planes fly shorter routes.

One expert said as many as 72 of the new Pratt engines have been taken off the wings of A320neo aircraft for inspection or repairs since entering service.

As of mid-April, Airbus had delivered a total of 100 A320neo aircraft since the fuel-efficient plane entered service in January 2016, including 53 fitted with Pratt & Whitney engines and the rest with CFM engines.

These include 32 so far this year out of a total of some 200 targeted for 2017 as a whole.

Chief Financial Officer Steve Priest said swapping the neos for the ceos between 2018 and 2019 “is just prudent” for the carrier.