For a plane with how many seats? Screenshot suggests 4ish passengers, though the aircraft looks like it could carry more.
Am I missing something and this is a per-person cost? That surely wouldn't gel with the statement about it being a more affordable option for flights shorter than 300 miles?
For short flights, a heavy jet wouldn't be cheaper. But when you start looking into singles, twin engines or turboprops the prices for a short flight can become very competitive and affordable... especially when time is factored in.