Note that the AA service is targeted for international travel, not domestic travel, hence the 767/777 selection and the international carrier. I don't think UA offers the international service.

Seems pretty unlikely that MD80's will get inflight telcom. Perhaps, 737's will get Connexion someday but it will be a while.

At least, AA was the airline that initiated the charge to allow us to use cellphones once we cleared the runway. Others (but not all) followed, but AA took the time, effort and money, to get the initial data and to get permission.