title_body: What affects the total flight time for a drone? What factors would affect a drone's flight time? Battery capacity? Weight? Anything else?
upvoted_answer: I'd watch out for several factors:
  1. Weight
  Drop any additional weight that you don't absolutely need for functioning.  This may mean downsizing to smaller motors, which obviously means that you have to balance weight vs. power; you may be able to get your flight time much longer but at the expense of speed.
  2. Battery
  Obviously the more juice you got, the longer you can go for.  Again, though it's going to be a balance between the weight of your battery... go for lighter technologies like LiPo.
  Also, make sure you've got new batteries on your drone; as your batteries age, they'll lose juice and capacity.
  3. Motors
  If you really want to increase the flight time... go for lighter less powerful motors.  Of course, you won't be able to go as far, so that may not be a tradeoff you want to make.
  4. Weather
  Make sure you're flying your drone in dry weather... Condensation or water droplets will both add resistance to any moving parts and weight.  Also, when the weather is well below freezing you'll notice that your batteries will start performing less well, as well as having increased friction.
  5. Maintenance
  Keep all moving parts well greased!  As friction increases, the amount of battery power you use will increase in consequence.
  Also, make sure all contacts remain solid.  Though it's not a big issue with newer drones, rust in the contacts / loose contacts will eat power.