This makes lower tier units better for stacking to improve speed.
Good point, an observation with interesting implications... Technically high-tier flight can still stack speed fairly well, since with the extra support you can afford a heavier/better cooling system, for example, though that's not even necessary if you're traveling light in the first place, where low-tier will apparently do.
I need to trigger the trap pronto.
Okay, well, don't worry about it since in Alpha 10 I'll add your dive key for you
edit: What if all flight units had the same maintenance costs and simply improved on other stats as you found better units? This was the change I thought you were making when you announced changes to flight.
Well I
mostly did that, by dropping all movement costs to the same values, because the biggest culprits making high-tier flight inordinately difficult to maintain (to the point of not being worth it) were those costs, since they would stack to ridiculous heights as you moved faster, up to 10-15 times per turn.
By maintenance I assume you mean upkeep, and those were left in because by the latter half of the game they only range from 2-3 instead of 1-2, a rather minor price to pay considering they'll give you 2x/3x/4x as much support, and you can use a small portion of that support to cover the costs incurred.
It's still possible to lower the upkeep a little bit, though the changes elsewhere were already quite drastic. If you compare overall energy/heat movement now to what it was before, it's gone down by a huge margin. I would think this is a strong contributing factor to flight being more reliable now, since you have to wait around to recover energy or dissipate heat less often, no?