However, visitors were still able to climb onboard the DC3, as well as the two aircraft that will fly the Whanganui route: the 34-seater Saab 340, which will operate the daily flights; and the smaller Fairchild Metroliner, which will run in the weekends.
The day also included displays of aircraft, vintage cars, and plenty of food and drink. There was a short ceremony in the airport terminal, which included a blessing from Whanganui iwi and speeches from Mayor Annette Main and Mr Emeny.
Ms Main said she hoped Whanganui people would do their best to support the new air service.
"I think you can see the support already from the number of people here today.
"It is unthinkable that a place the size of Whanganui could have no flights, so we really have to help you make this work," Ms Main said.
Mr Emeny shared some of the history of Air Chathams, which has been operating for 31 years. It started as a way of getting to and from the Chatham Islands, and a way to quickly transport the Chathams' lucrative crayfish catch to the mainland.
He acknowledged the Air Chathams staff, who had helped pull the Whanganui service together in just six weeks.
"Whanganui is part of our Air Chathams family, and we are reliant on you to make it work," Mr Emeny said.
Air Chathams' general manager Duane Emeny said despite the weather, he was very pleased with the turn-out at the open day.
"It was busy all day. It was really heartening to see so many people there."
The first Air Chathams' flight leaves Whanganui at 6.55am on Monday.
