BA = fab because you can get the recliner seat instead of the bassinet, which is better for bigger babies.
I took DS2 home to the UK in March/April this year, we flew BA, DS2 was 6mo. He was already too big for the bassinet so the recliner seat was great - it has 2 positions, lying flat for sleeping and more upright (but not very) so baby can look around when awake.
Tips:
DEFINITELY delay weaning until you get home.
Feeding baby on take off and landing helps with the ear popping and so they don't scream with the pressure change.
Some 4+m fruit pouches are excellent for taking with you, fruit and/or veg in easy to swallow format.
I took an umbrella-fold stroller with me because my back is too bad for me to have coped with a nearly 10kg (~22lb) baby on my front AND lifting 3 suitcases. Luckily it came in the cabin with me both ways, so I had it at the stopover (necessary).
One of those little "airhostess" style zipped trolley bags is brilliant for the cabin luggage - have all the nappies and change stuff right at the top end, so that when it's in the overhead locker, you only need to unzip the top end and put your hand in to pull out what you need - saves a lot of time.
Definitely need change of clothes for you as well as the baby. Probably more than one.
I think I'm just going to be repeating what everyone else has said now so I'll stop - but yes, a 6mo is relatively easy. I am sooooo not looking forward to next year's trip, when he will be 18mo and mobile - eeek! Thankfully DS1 is a seasoned traveller at 5 and can pretty much sort himself out now.
I didn't find jetlag was too bad for DS2 - his sleep wasn't exactly in a set 10h a night pattern anyway! - but it takes me and DS2 about 3 days to get over it (but that's Australia to the UK, so more time zones to worry about).