The Portland International Jetport has lost 400 to 1,000 parking spots since May because of maintenance and construction.

The number of passengers coming through Portland International Jetport has grown so much that parking is becoming a problem even though a five-story parking garage was built less than a decade ago, and some travelers have complained that officials haven’t done enough to notify them.

On Friday, the jetport website advised passengers planning to park at the airport to budget an additional 30 minutes in case they need to leave their vehicle at a discount lot roughly 10 minutes away.

“This week has been really aggressive,” Airport Director Paul Bradbury said.

Long-term parking demand is typically low during the summer, when many passengers flying in on vacation rent vehicles or get picked up at the airport. The lull coincides with construction season, when the airport sacrifices a number of parking spots so it can do work on the garage.

But with the top two floors of the parking garage closed this summer for regular maintenance and installation of a rooftop solar array, the airport didn’t have enough space to meet the surge in parking demand.

Unexpectedly full parking lots have made an already hectic travel experience worse for some people.

“I get it, people arrive at the airport already stressed and concerned about their flight,” Bradbury said. “The last thing they want to think about is ‘Where do I park?’ ”

Since May, the jetport has lost between 400 and 1,000 parking spots because of maintenance and construction, about 17 percent to 43 percent of the airport’s total capacity. During a normal summer, the jetport would have enough parking even with the reduced space, but the last two months have been anything but normal.

Passenger volume through the jetport grew 19 percent in June and 20 percent in July, compared to the same time last year, Bradbury said. In July, almost a quarter-million passengers passed through the airport, a new monthly record. The number of passengers has grown by 200,000 in the last five years, to more than 1.8 million in 2017.

The unexpected surge complicated a “very thoughtful” plan to make sure there was enough parking, Bradbury said.

“We are seeing more parking needs just due to the Frontier capacity that started July 10,” he added, referring to Frontier Airlines, the ultra low-cost carrier that started flying from Portland to Florida, Colorado and North Carolina this year.

To manage the overflow, jetport officials opened a remote lot on District Road west of Interstate 95, about 2 miles from the main terminal. The 450-spot parking area is now open on an as-needed basis, but the jetport plans to renovate the lot and keep it open year-round with cheaper rates – $8 per day instead of $12 a day – than the parking garage or lot at the airport. Shuttles will bring passengers to and from the remote lot.

Even before this summer, the jetport was already having parking issues. It was forced to open its remote lot a few times during the winter, when parking demand is the highest, Bradbury said.

“Our expectation is that it will be sufficient to meet demand, but at some point it may fill up as well,” he said.

The new arrangement doesn’t seem to have been well communicated to travelers, however.

Tom Keller of Portland said he and his partner typically don’t leave a lot of lead time when they fly out of Portland.

“Usually, we cut it close, because it’s Portland and we have TSA Pre (expedited security),” Keller said. “Unless you are doing the morning flights, you can usually get through.”

But his partner scrambled to make a flight this week after she was diverted from the terminal parking to the remote lot.

“She made the flight, but it was close,” Keller said.

Bradbury acknowledged the jetport hasn’t made many public announcements about the parking issue, mostly because the need to use the lot has changed day by day. When it opens full time, there will be better communication, he said.

The parking crunch has been good for Park’N Jet, a company that operates a long-term lot near the airport and shuttles customers back and forth to the terminal.

Manager Matt Maher said on days when jetport parking is full, he’s seen a huge number of new customers. They get about 30 or 40 vehicles on a normal day, Maher said, but on the days jetport parking is stretched, demand has soared.

“On a couple of days, we’ve had well over 100, 150 vehicles all at the same time,” Maher said. “We’re definitely noticing it.”

The jetport’s current garage was built in 2010, before a major expansion that doubled the size of the passenger terminal. More parking is included in a $312 million, 20-year master plan for upgrades and expansion at the airport.

Including the discount lot, the airport has 3,060 public parking spots to meet current demand of 2,498 vehicles, according to the 2016 master plan. The public parking capacity should be enough for the next 10 years, but demand will exceed supply within 20 years, according to the plan’s projections.

Jetport officials may have to move up plans to add more parking if passenger numbers keep soaring, Bradbury said.

Peter McGuire can be contacted at 791-6325 or at:

pmcguire@pressherald.com

Twitter: PeteL_McGuire