The Medford airport was back in record territory during March.

Spurred by United Express' 21 percent gain and Alaska Air Group's continued growth, passenger activity eclipsed the year-old March record by nearly 4 percent. A total of 64,780 travelers passed through the gates last month, bettering the previous standard of 62,341.

Airport Director Bern Case said seating capacity grew 9 percent in March. With the addition of United trunk-line 737 flights on the San Francisco route in early April, there are 14 more seats with the same number of departures as a year ago.

The popularity of larger aircraft has peripheral ramifications, Case said.

"The restaurant is putting on additional people when those flights are scheduled, and the parking lot is opening a second booth for those key times," he said. "When the parking lot is full and rental car lot is empty, that's when we know this place is humming."

Alaska Air Group's Horizon Air unit accounted for more than half of the March traffic, with 34,484 passengers, a 3.3 percent gain. United transported 17,390 travelers, Delta Connection recorded a 5 percent drop, and Allegiant Air was down 19.2 percent.

Rental car activity reflects the broader economy, with business travel accounting for 50 percent of the passenger count.

"They pay higher fares, and they rent cars," Case said. "Not all of the passengers have the same impact. Business travel affects the bottom line more positively. We do get some people visiting Aunt Mabel who still rent a car. But business people almost always rent a car. If it got up to 55 percent, that would be good."

There were 56,669 daily rentals (counting each day a vehicle is out) in 2016 from Alamo, Avis, Budget, Enterprise, Hertz and National in 2016, up from 52,043 in 2015. After a slower start this year, March rentals were within 103 of the 2016 figure after a strong March, when 4,333 vehicle days were logged.

Both passenger and vehicle numbers could get a bump in June when American Eagle launches service to Phoenix Sky Harbor and Los Angeles International airports.

TSA PreCheck registration continues through Saturday at the airport's Oval Office.

Case said TSA has averaged 150 applications since April 11.

Travelers can schedule an appointment ahead of time and can begin the process by calling MorphoTrust Call Center at 855-347-8371. Flyers may also go to www.tsa.gov/precheck.

Hours are 3 to 7 p.m. Walk-in enrollments will be accepted, but there may be extended wait times, with scheduled appointments taking priority. Enrollment cost is $85 for a five-year membership.

— Reach reporter Greg Stiles at 541-776-4463 or business@mailtribune.com. Follow him on Twitter at www.twitter.com/GregMTBusiness, on Facebook at www.facebook.com/greg.stiles.31, and read his blog at www.mailtribune.com/EconomicEdge.