By Isabel Goyer Recently an all-electric Robinson R-44 helicopter made a flight from Jackie Cochran Regional Airport in Thermal, California, to nearby Palm Springs, a trip that covered just over 20 miles, making it less than half the distance as a flight that qualifies as a cross-country. It was a hop. The same helicopter, being modified by Tier One Engineering, made its first flight in June. The helicopter can be charged in about an hour or have its batteries swapped out for charged ones reporting in a fourth of that time. The batteries are huge, as you can see in this photo, and Tier One has…