Delta Air Lines, the dominant carrier at the Minneapolis-St. Paul International Airport, is advising passengers flying on morning domestic flights to arrive three hours before their departure time due to construction at the airport's main terminal.

In an e-mail sent to passengers departing from MSP, Delta recommends arriving three hours ahead of time for domestic and international flights leaving before noon. Delta flies out of Terminal 1, also known as the Lindbergh terminal. The Atlanta-based airline confirmed the advisory this week.

"I got an alert from Delta to be here early and I was like, 'What else is new?' " said Margo Tantau, who lives in the Seattle area. "I lived [in the Twin Cities] for eight years, so I'm familiar with the lines here."

In mid-August, the Metropolitan Airports Commission (MAC) announced that the two security checkpoints in Terminal 1 would be reconfigured to accommodate construction at the south checkpoint. The new arrangement, which is expected to end in mid-December, has resulted in unpredictable and sometimes long security lines in Terminal 1, particularly for those leaving on morning flights.

Sharon Peterson of Minnetonka got to the airport at 7:30 a.m. Friday, leaving plenty of time for an 11:20 a.m. flight to San Jose.

"I had already planned to get here three hours ahead of time," she said, noting her airport shuttle arrived an hour early. "I think I'm too old-fashioned, plus I'm retired and I have lots of time."

The airport and the Transportation Security Administration (TSA) still advise travelers to set aside two hours before domestic flights, and three hours for international trips. Only Delta advises arriving three hours before a domestic flight before noon, and two hours after that.

Now, passengers with TSA PreCheck and Clear with PreCheck must go through the security line at the south checkpoint. Travelers who do not have TSA PreCheck, and those who are First Class/Sky Priority or have just Clear must use the north checkpoint.

Another checkpoint for travelers with carry-on luggage is located on the third floor of the Intercontinental MSP Airport Hotel, which opened in 2018. The checkpoint, connected to Concourse C by skyway, is open from 5:15 a.m. to 10 a.m. daily. A skyway checkpoint between concourses C and G remains closed due to TSA staffing issues.

Labor Day is typically a busy travel time at the airport, but not excessively so, said MAC spokesman Patrick Hogan.

"Most families have already had their summer vacations and stay closer to home during the Labor Day holiday, getting ready for the school year to begin," Hogan said. "The number of people flying won't approach what we saw even a couple weeks ago, when people were still taking late summer vacations."

Still, some people Friday morning found themselves stuck in a long security line.

Hugh Ocampo, of Minneapolis, was traveling with his wife and three children on a Spirit Airlines flight to Los Angeles that was supposed to leave at 6:30 a.m. Unaware of the security line issue, Ocampo arrived at the terminal at 5:30 a.m. and missed the flight, requiring him to buy new tickets on United Airlines.

"It was crazy," he said of the long lines.

Some Delta travelers have encountered a double whammy — long lines to check their bags, and then long security lines, as well.

The checkpoint construction is part of a multiyear, $1.6 billion overhaul of the terminal.

Janet Moore • 612-673-7752

Twitter: @ByJanetMoore