DENVER Winter weather combined with the busy holiday travel caused some impacts for passengers at Denver International Airport (DIA) on Wednesday.According to FlightAware, more than 500 flights were delayed as of the early afternoon hours.Passenger, Kelly Mannings, said it was the final rush for her to make it home in time for the holiday."I'm headed to Sandpoint, Idaho to spend Thanksgiving with my 88-year-old mother and my sister and I get to go see my new great-nephews. So I'm very excited," Mannings said.Mannings told Denver7 she was aware of the severe weather and expected the airport to be busy, so she made sure to plan ahead."My flight's not until 3 p.m. so I'm here at 11:30, I thought I'd get here early," Mannings added. Denver7 spoke with airport officials who shared a close look at how they keep planes safe before departure during severe weather days like this. "Our primary responsibility is closing runways so that the snow removal crews can get out and clean the runways," Mike Carlson said. He's the assistant director for airside operations at DIA, "And then, once that is complete, we will send a notice to air missions, so that the pilots and incoming pilots know what type of weather to expect."Carlson said crews have to deice the planes ahead of take-off. He said the process can take 15 to 20 minutes or longer, if the plane has been at the airport overnight.He said they use both Type I and Type IV glycol, which is used as used as deicing fluid.The glycol is sprayed on aircraft to remove frost, snow and ice from the wings and protect against refreezing before takeoff."Type I is just to knock off any ice that may have accumulated while the aircraft is at the gate, and then the Type IV is what they put on it's a thicker glycol which allows the aircraft to get up off the ground as they depart," he added, saying it keeps it from icing.Carlson said crews have stayed busy throughout the day but haven't run into major issues. "I think it's going to go very well. We had to get out first thing this morning, and we put liquid chemical on the runways to keep the runways from icing over. And since then, we haven't had to go back out. And I think we're on the downhill side of this storm, so we should be in pretty good shape," Carlson said. Travelers also said they're pleasantly surprised at how smooth things have gone for them so far. "It's actually a little slower than I expected. I thought it would be busier," Mannings said.