I've made some stupid mistakes on accruing miles this year. It's my first year traveling for work and just didn't think it through. I have the following qualifying balances:

AA: 11.7k
Delta: 9.4k
UA: 9.6k
US: 20k

I need to book IAD -> LAX -> MEL and back for early November, along with some other domestic travel, and I'm trying to figure out where I should put those miles. The travel to Australia could either go on UA/US or AA and another 4 or 5k in domestic travel could also be UA/US or AA. The trip to Australia will put me in Silver on US and the additional domestic travel would put me in Gold, so I'm leaning toward booking on UA and using my US number.

But, I'm concerned about what's going to happen with this merger and the potential transition from *A to OW.

I'm going to be doing probably 50-75k miles next year as well, including one or two SE asia or Europe trips, but mostly domestic RIC/IAD to AUS, DEN, and SFO.

Any advice is greatly appreciated.