Crew members escorted the passenger, a man in his late 50s whose name was withheld, from United Airlines Flight 662 to San Francisco about 7 a.m. and turned him over to San Diego Harbor Police officers, SDHP Lt. John Forsythe said.
Authorities originally characterized the man's comments as threats, but investigators determined that the man had made no threats, committed no crime and apparently was in need of some mental health assistance. He was taken to a psychiatric hospital for an evaluation, Forsythe said.
The exact nature of the man's statements was unclear. Forsythe said they likely involved the airport and subway-station attacks that occurred several hours earlier in Brussels and left dozens of people dead and many more injured.
The San Diego resident's comments simply "made (fellow passengers) nervous, especially since he kept repeating himself,'' the lieutenant said.
The flight departed slightly behind schedule and arrived on time in the Bay Area, according to the airline.