Ryanair is in talks with Boeing about placing an order for its proposed new 737 MAX 10 airliner, two people familiar with the matter have said. 

Boeing is expected to launch what would become the largest version of its 737 MAX medium-haul family, designed to challenge the popular Airbus A321 flown by Ryanair rivals, at the opening of the Paris air show next week. 

Ryanair, which was the launch customer for the 196-passenger Boeing MAX 200 aircraft in 2014, is in discussions about buying the new plane which seats up to 230 passengers, the people said.

It currently only flies 189-seat 737-800s. 

It was not clear if a MAX 10 order would be in addition to or at least partly a substitute for the MAX 200 order for 100 planes. 

Talks are progressing but it also remained unclear whether a deal would be ready in time for the June 19-25 air show, one of the people said. 

Ryanair rarely attends such events and is expected to hold out for the best possible price before placing an order. 

Ryanair executives have said repeatedly in recent months that they would be interested in additional aircraft if they were available at the right price, saying the only thing curtailing faster growth was a lack of available planes. 

The airline's chief executive Michael O’Leary said in May Ryanair was talking to Boeing about opportunistically adding planes to its current order and for additional orders to cover growth from 2023 to 2028. 

The latest talks come as Hungarian rival Wizz Air shifts from the 180-seat A320 to A321s which can carry up to 239 passengers and has said it hopes the larger planes will help bring its unit costs below those of Ryanair.

UK budget airline EasyJet said in May it would take 30 Airbus A321neo jets with 235 seats from next summer, instead of 30 smaller A320neo planes.

It said this would enable it to reduce costs per seat on affected trips by around 8-9%. 

Indonesia's Lion Air is also preparing to place an order for the 737 MAX 10, Reuters reported last week.

Industry sources said the carrier could order about 50 planes but that some may displace earlier orders for other 737 models.