The passengers had just made sure that their seat belts were securely fastened for United Airlines Flight 399 yesterday when the woman in seat 7B spoke up: "Can you show the hearings on this flight?"

Several more passengers aboard the Denver-to-Seattle flight seconded the motion, and the crew promised to tune in on the aircraft's movie screens as soon as they could pick up a television signal.

In a few minutes, Marine Lt. Col. Oliver L. North and Senate chief counsel Arthur L. Liman appeared on the screen, and the passengers fell to kibitzing.

"You know, I just love that guy North," said 4C, a white-haired gentleman.

"Really?" deadpanned a flight attendant. "What did you love best -- when he lied to Congress or when he sold missiles to the ayatollah?"

"Lay off the guy," chimed in 2B, a middle-aged man in a green golf shirt. "He followed orders like any good Marine."

"Yeah," agreed a young woman one row back, "and he's doing a lot better in that chair than any of those senators could."

Across the country this week, Americans praised North, excoriated North and didn't know what to make of North. Not since former White House counsel John W. Dean III testified during the Watergate hearings 13 summers ago have so many people gone to such lengths to watch a congressional witness. Those who weren't interested in his testimony had to go to nearly equal lengths to avoid it.