HARRISBURG, Pa. (WHTM)– Holidays aren’t what cause holiday travel messes, but what does cause them?

The same thing that causes travel messes when it’s not a holiday weekend… bad weather

“Smooth sailing,” Josh Leinart said.

Leinart arriving in Harrisburg from the world’s busiest airport, Atlanta, on his way to where else?

“Going to a Penn State game,” Leinart said.

He was ready for anything at the airports, but the reality?

“For a Labor Day weekend, it was a piece of cake,” Leinart said.

Was Leinart just lucky? Well, if he was so was everyone else at Harrisburg International: every flight was scheduled to leave on time.

The only flights that weren’t arriving on time were arriving early. If you’re surprised by that airport spokesman Scott Miller says you shouldn’t be. Busy travel weekends don’t cause delays and cancellations. Bad weather does.

“If the weather is good and the hurricane’s gone, so if that’s good, the airline system should work pretty well nationwide,” Miller said.

20,000 people are expected to come through here between Thursday and Tuesday.

“That’s a few more than we had last year,” Miller said. “Probably four or five percent more than we had a year ago at this time – mostly because airplanes are flying bigger planes. So while we don’t have quite as many actual flights, we’re getting more people in the building because they’re just larger airplanes with more seats for sale.”

Good weather has a mixed impact on car travel. No slick roads and that’s good, but makes driving more attractive.

“So we expect to see a lot more people out on the road,” PennDOT spokesperson Fritzi Schreffler said. “A lot of people will take advantage of going to the beach, going to visit family for what they consider one last vacation.”

So more cars mean slower traffic.

“But we also want to assure people that there will be more police on the road,” Schreffler said. “We’re in the middle of a national crackdown on impaired driving.”

Two key words there are “impaired” and “national.”

Impaired means because of anything – whether alcohol or drugs, legal or illegal. “National” means just what it says — cross into Maryland, West Virginia, or whatever other state and cops there will be just as tough as the ones in Pa.