Technician doesn't boost a move that is power uped by a gem (if the base power is above 60 after gem boost). The item is calculated before other checks, so the gem is used up before Technician is applied. I can't find you a source for this, but I've tried it out in-game and my Scizor didn't do as much damage as it should have with Flying Gem Acrobatics if Technician boosted it.
Therefore, Aerial Ace will have a BP of 90, and will not qualify for Technician boost.
There is therefore no point in using a gem for Aerial Ace, since the boost from Technician is exactly the same as the boost from a gem, i.e. x1.5 or 50%.
