high altitude

Has anyone noticed that the batteries drain faster at high altitude? It make sense because of the thinner air, the motors must work harder. I was flying yesterday at about 6300 ft elevation. TH still flew fine but not as long.

Does anyone know if there will be props with a higher pitch for flying in areas like Colorado, Wyoming, etc..where the altitude is 5,000'+? I'm planning on a trip to Wyoming in October but I would prefer to find some props that are better suited for that altitude. I basically want to avoid...