an airport at 2500 feet vs sea level and landing distances...
an airplane needs to approach a field at an indicated airspeed based on weight (additivies for wind)...that speed is the same regardless of elevation of the airport
but here is the rub
if the indicated airspeed is the same at sea level and 2500 feet...the TRUE AIRSPEED is higher at 2500feet/ this means a higher ground speed and a longer landing run than at sea level.
google things like ''density altitude'' or "high density altitude" for greater details.
note; HIGH density altitude does'nt mean that the density is high!