my friend and i got into a discusion, were trying to figure out how these characterictics affect flight and lift and speed on our model aircraft

low altitude compared to high altitude (we fly at 8000' msl, so the air would be thinner correct? - but do we need to go faster to lift off?)

hot days vs cold days

low humidity vs high humidity

and how does barametric pressure relate to humidity? or does it all?

thanks


mainly im interested in what these things do to speed and lift

thanks