> The problem with lithium batteries is they are heavy... McDougall says battery technology is advancing quickly and he expects them to be even lighter and more

> The problem with lithium batteries is they are heavy... McDougall says battery technology is advancing quickly and he expects them to be even lighter and more powerful, as his project gets closer to flying commercially. > Antweiler says Harbour Air is in the "sweet spot" in the industry as its flights are short, meaning battery technology as it stands today makes the project viable.