I went woff to answer my own question and changed player flight altitude to medium. Campaign loaded balloon busting with "A-Flight" assisting.
TAC info wants us to fly at 7,000 ft and "A-Flight" is above and behind us.
That change seems to have fixed things for me. Will see if it continues to do so on other mission types involving "A-Flight". Time to check out the rockets on the early Nupe and try to take out a balloon.