SAIGON — Sights and sounds of the Nixons' visit to Vietnam:

— Air Force One, the presidential jet liner, spent most of the afternoon in Cam Ranh Bay after depositing the Nixon party at Saigon's Tan Son Nhut air base at noon. The glistening Boeing 707 returned shortly before 5 p.m. for the trip to Bangkok. Its 707 counterpart, a Pan-Am plane chartered as a press flight, stayed in Saigon all day.

— Saigon traffic, normally a maniac's delight, was even worse all afternoon as Vietnamese police blocked off a wide area around the presidential palace. Security precautions were naturally super-stringent; Vietnamese military policemen turned out in sparkling white uniforms on the palace grounds.

— Helicopters and jets maintained day-long surveillance over the congested Saigon-Long Binh-Di An area where the President and Mrs. Nixon spent the afternoon. Over 20 choppers, including at least six Cobra gunships, patrolled the Di An skies as the President talked to troops and, above the choppers, was a flight of F100 jets.

— Troops at Di An knew something was coming but not exactly what until about two hours before President Nixon actually arrived by helicopter which had earlier flown him from Tan Son Nhut to the palace. Maj. Gen. Orwin C. Talbott, 1st Div. commander, had called a "practice red alert" at Di An for early morning, so the base was tightly secured with most of the troops in bunkers and fighting positions.

The 250 men in the two companies Nixon visited had been warned two days earlier that they faced a "general inspection" Wednesday. With that in mind, the troops were all spit and polish. They learned two hours before Nixon arrived that he was enroute.

Each man Wore a new helmet cover, equipment was tidied up and, as one observer put it, bunkers on the perimeter "looked as if they'd been vacuumed."

-— Pfc. Franklin Walraven of San Bernardino, Calif,, may surprise the Nixons in their new home in nearby San Clemente. When Walraven told the President where he lived, Nixon mentioned the new house and invited Walraven to "come on down swimming any time the pool is open." Walraven later said he might take the President up on the offer.

— Many Di An troopers were interested in Nixon's reaction to the Apollo 11 moon landing success. Speaking without a microphone, with one hand in a pocket while the other roved his windblown hair, Nixon said, "They (the astronauts) proved we've got some guts left in this country. You guys are doing the same thing."

— Mrs. Nixon not only visited with wounded American soldiers at the 24th Evac Hospital in Long Binh, but charmed them with a warm smile and ready conversation.

The First Lady had a short briefing by the hospital commander, Col. Claude McClure Jr., then said, "let's go say hello to the men." She did, greeting 39 GI's while Madame Tran Chanh Thanh, wife of the Vietnamese foreign minister, visited a ward housing Vietnamese and American patients.

When Pfc. Jerry Collier of Houston, bed-ridden with an injured foot, told Mrs. Nixon he was awaiting his hometown paper in the mail, she brought a quick smile by saying, "when my husband was in the service, I sometimes got letters in batches of 30."

Mrs. Nixon asked another trooper if the pocket book at his side was a mystery novel. "Not exactly, m'am," he confessed. Picking it up with a glance at the cover, the First Lady grinned and said, "my goodness, it looks racy."

Meanwhile, Madame Thanh entered a ward and began talking to a wounded patient who stared at her somewhat blankly. She didn't discover why until the next patient told her, "that fellow's a Cambodian. He couldn't understand your Vietnamese."

— During an earlier visit to the Thu Due orphanage, Mrs. Nixon was offered an Ao Dai, the flowing Vietnamese dress, by Madame Nguyen Cao Ky, wife of the Vietnamese vice-president. "I already have one," said Mrs. Nixon, who was making her third visit to Vietnam.

— Three members of the White House press photographers gallery took advantage of a short breather in the hectic palace schedule to admire the camera bag carried by a chap who said he'd had it made by hand in Saigon. Within minutes, the trio had forked over cash for similar bags.