A Denver-area company that’s trying to build a new type of airplane said it’s going to try again and raise funds. Centennial Airport-based XTI Aircraft Company, which is trying to raise money to build a six-seat airplane that can take off and land vertically like a helicopter, originally tried to raise $3 million earlier this year but fell $1.8 million short. Now it’s trying again. “When the company didn’t reach the minimum of $3 million by April 30, it refunded the investments and temporarily…