Take the train or plane from Malaga to Barcelona

You may be interested in reading Nigel's reply to this thread: https://community.ricksteves.com/travel-forum/general-europe/train-or-plane-paris-to-florence

Nigel's reply does not pertain to your route, but he explains the advantages of train travel vs plane travel, in great detail ;-)

You must take into consideration the time it will take you to get to the airport, waiting at the airport, plus the transfer (& cost) to your hotel upon arrival in Barcelona.

I've not traveled this route, so can't comment, but hopefully others will chime in with their experience.

Have a wonderful trip!

I would take one of the direct trains, about 3x/day, under 6 hours, not for scenery but for simplicity. Both train and plane tend to be cheaper when reserved in advance.

Plane 1hr 35min vs Train 5hr 45min
I'm not familiar with AVE route from Malaga to Córdoba, but the remainder is not really scenic at all. Your estimation of a 2 hour time difference seems spot on. Line ball call for me. It would for me depend on your wider trip - a flight perhaps to mix it up if you have lots of other train transfers.

Google maps shows the time to get to the train station and the airport in Malaga to be about the same by taxi - 15 minutes. In Barcelona, there's a bus from the airport to Plaza de Catalunya every 5-10 minutes, 35-40 minute ride. I flew international into Barcelona and it only took a few minutes to get through the airport. Malaga's airport isn't huge, you probably don't need a lot of time there.

If you are staying very close to the train station, it may save a little to get to your hotel vs. from Plaza de Catalunya, but overall, I'd go for the plane. I took the train from Malaga to Sevilla in March, there was a little bit of interesting scenery that I almost missed, but mostly just pleasant and missable. On the other hand, short flights generally fly lower, so it may be a scenic flight.

Thanks everyone for your help.
i think i will fly.
Happy travelling.