Oct 14 (Reuters) - Chinese planemaker COMAC has painted

one of its ARJ21 regional jets with C909 branding, aligning with

the manufacturer's naming conventions for its other models,

according to photos posted on aviation enthusiast forums and

Chinese social media.

Although largely symbolic, a possible rebranding ahead of

China's main air show in Zhuhai next month signals Beijing's

growing intention to present itself as a full-scale alternative

to Western plane giants Airbus and Boeing ( BA ).

An ARJ21 plane was photographed with "C909" painted on its

blue tail at Shanghai Pudong airport on Sunday by two users of

plane-spotting website jetphotos.com and one user of

planespotters.net, and other images of it appeared on Chinese

social media site Weibo on Monday.

Reuters has been unable to independently verify the photos.

COMAC did not immediately respond to a request for comment.

The ARJ21 entered service in 2016 and is operated by various

Chinese airlines and Indonesian carrier TransNusa. But market

analysts say the regional aircraft, China's first jet to reach

commercial production, remains uncompetitive globally.

COMAC's subsequent plane, the single-aisle C919, entered

service in 2023 and the planemaker has said it is designing a

twin-aisle plane called the C929. The company has also hinted at

an even larger C939 in the future.

The C929 was renamed in 2023 from the CR929 after Russia

left a China-Russia joint venture developing it.

The photographed plane, painted with registration number

B-099A and manufacturing serial number 10156, belongs to COMAC

and is registered as an ARJ21 test flight aircraft, according to

Flightradar24 tracking data.

On Monday it conducted what appeared to be a test flight

from Shanghai Pudong airport, Flightradar24 shows.

The International Civil Aviation Organization's aircraft

type designator database still records COMAC's regional jet as

the ARJ21. ICAO did not immediately respond to a request for

comment.

The practice of renaming models to create a single brand is

common in aviation. Airbus in 2018 renamed Bombardier's CSeries

the A220 after buying the programme.

COMAC this year has increased sales and production plans and

has been marketing its planes outside China. But industry

sources caution COMAC is a long way from making inroads

internationally, especially without benchmark certifications

from the EU - which COMAC is pursuing for the C919 - or the U.S.