Barcelona-Madrid 10 days - Round trip flight or train?

Definitely go by AVE fast train, stations would be Barcelona Sants & Madrid Atocha, travel time around 2 1/2 hrs, booked on Renfe.com.

Madrid to Barcelona is a high speed route - 3 hours or less.
I put it in the Renfe site for a random day next month and there are over 10 trains per day that take 3 hours or less. To buy use renfe or a third party site (I used petrabax once when renfe was being difficult)
Make sure you use the right station, or Madrid (todas) and Barcelona (todas) if you're not sure. And don't look too far in the future right now - schedules shift in June.

The website maninseat61 has amazing train information

The argument against a flight is simply that the train is faster (counting the fact that you need to be at airport early, and transit to/from the airport to center city). If the train were actually 7 hours then it would be different. But on the AVE route, it's faster and easier. Plus trains are rarely cancelled or seriously delayed, unlike flights.

The problem is the labeling of the rail stations in Madrid. If you choose Madrid-Atocha Cercanias, you get only local/regional trains. You need to choose Madrid-Puerta de Atocha or Madrid (Todas)--as previously suggested--to see the fast trains.

Ah yes. I see.
After I posted, I played around with the selections and was able to see more trains and the various schedules.
I'll wait til after June to finalize the itinerary

Question on the flights - why would it take longer than 3 hours? Is it considered a domestic flight? Typically we check in online, go through security and right to the gate. For domestic flights in the states I typically arrive with 30min to spare. Is the process more cumbersome from Barcelona to Madrid? Not sure if there will be passport checks, etc or if it's just like flying from Miami to New York for example.

Thanks again for the helpful feedback
;-)

Flight including getting to and from the airport to the city is certainly longer than 3 hours. And to arrive to the airport thirty minutes before flight?? Try it in Seattle and I guarantee you plane would leave without you. First you have to have some reserve. What if you get stuck in traffic. Then what if you need to check your luggage? Even if you don't need that you have to go through security. You don't know what kind of line will be there. Sometime you spend your thirty minutes (or more) just in that line. Then you have to get to your gate - 5 minutes, 10 minutes or more? Depends on the airport. To get to the airport thirty minutes before the departure? Those were good old times. Forget it now. No passport check. Just ID check - in your case probably passport. Not only are Barcelona and Madrid in Schengen area, they are also in the same country - Spain.

LOLOLOL Come on, why so jaded? :-) Just kidding.
I do it all the time - of course in an airport I know like Miami and Fort Lauderdale (I'm also spoiled cause I live near the airports, thankfully). I do allow myself ample time when it's a first time airport so I do understand the advice. I just didn't think it would be more than 3 hours - sound kinda crazy as even on a bad day with all kinds of delays it's never taken me 3 hours to get on a plane, whether domestic or international.
But I will heed the warning which is much appreciated ;-) Thanks again! And here's to some of the good stuff from the good old days coming back LOL

Edit: That's what I figured about passports and IDs with it being in the same country. Just wanted to double check ;-)

Don't fly - besides all the info given above, add on the 35 minutes transit from the city to BCN and then again MAD to the city. The train is a no brainer.

Thanks for the input ;-)
It's been decided - train it is